Engine Modification and Tuning Guide Coverwildaboutcarsonline.com/members/AardvarkPublisher... · 2016. 3. 7. · Engine Modification and Tuning Guide Oldsmobile Gen 2 V-8 Engines

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Oldsmobile

Gen 2 V-8 Engines from 1964 through 1987 Including the 260-403 Small Block and 400-455 Big Block

Developed Exclusively for: The Automotive History Preservation Society Copyright 2015 Use Without Permission Violates Copyright

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Forward I published the original of this manual back in the late 1970’s when Oldsmobiles and muscle cars in general had been relegated either to junkyards or sat dusty and unused in garages – mostly because of two colossal gas price increases, a huge jump in insurance pricing, and Uncle Sam’s new emission control regulations. As you probably know, by the time 1978 arrived, the American auto manufacturers had basically totally exited the performance marketplace.

In a single decade it was as if the knowledge of muscle cars and ways to increase the performance of the American V8 just disappeared – as if a comet had struck the Earth and killed off all that knowledge. That phenomenon still strikes me as weird to this day. As a gearhead who grew up in and around the horsepower crazed 60s and birth of American muscle car, I was amazed by the almost total loss of information about hopping up Oldsmobile 442s and Cutlasses. My friends and I would sit around and lament the fact that except for a few of us, everyone seemed to be a dunce when it came to extracting some performance from an Olds V8.

Then it struck me; it was I who was the dunce. I realized that: 1) there was a whole new generation of people who had been kids when these cars roamed the streets, 2) Olds had been kind of stingy in handing out performance information, and 3) there just had never been any real Olds performance publications out there. So one day I sat down and compiled all the information I knew about Oldsmobile performance parts and the factory muscle cars, and the original Olds Performance Manual was born.

Since then, I moved on to other things and the Manual ran out of print. But recently I have realized that the cars have been resurrected and are found everywhere, but once again all that lore has been lost. So our friends sat down and determined that the only way to recapture this information was to develop a website dedicated to the preservation and dissemination of things automobile. The offshoot of such is these Manuals – and this one is one of the keystones.

So here is Oldsmobile Performance - Part Three. Inside you will find many of the part numbers that can no longer be found in GM’s parts catalog and even on websites and forums. Many of the parts are still out there - either as NOS or NROS – so hopefully these listings will help. So grab this Manual and go for it!

Bob Gerometta

Palm Harbor, Florida March 2007

PS. Thanks to Dana Page and Helen Early of Oldsmobile Public Relations, who annoyed me until I did the first edition - and then supported me with tons of materials and pictures; my gearhead friends in Smithtown New York who helped print that first run; and Paul Tortorici, of Hackensack New Jersey who reinvigorated my desire to update the book back in the mid 1980’s.

And thanks to my wife Sue, who puts up with the tons of information I collect on performance cars and such and enjoys our current rides almost as much as I do.

The picture that graced the front cover of the original manual – circa 1977

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Introduction

General

This document is not intended to be the Ten Commandments of Oldsmobile engine modification – no document or manual could do that or be so perfect. It was and is intended to be a guide to those people wishing to get better performance out of their 1964 trough 1989 Oldsmobile - powered by an Oldsmobile Division V8 produced in that period. We've updated the original Olds Performance Manual with tips on the 403 and 307 Oldsmobile Division V8s, as well as information on improving the performance of the last body on frame car (G Body) that was produced from 1978 to 1987. Each suggestion will improve performance, but it will not turn a worn out, 200,000 mile oil burner into a ten second quarter miler.

Many will ask; “Why did you recommend this product over that one?”, or “How come you did not say anything about Zilch cams? They worked for me”. The answer is that the products we’ve recommended in this Manual were designed by people who had tons of experience in getting the most out of an Olds. And based on our own experience – these are the products that worked great for us and many other successful modifiers and racers. Some parts are no longer available across the counter, especially the factory pieces, but where we recommend them, they may still be the best for your vehicle. So we suggest that you scrounge the Internet and swap meets for them.

Another piece of advice: if you are unsure, use a factory performance part. Back in the day, the factory didn’t have race teams and performance companies using CAD and computer simulations to build replacement parts, but they did do extensive testing of what they did release and they took a lot of feedback from racers and the average Joe (something that seems to be a lost art). Take if from us – the old stuff works- especially on the cars that will see a lot of street time and an occasional sortie to the strip or road course!

Last, this manual makes no guarantee for any product. The manufacturer alone bears any responsibility for their products, not Wild About Cars, LLC, the authors, or anyone else mentioned herein. Check the guarantee and/or warrantee of any product before you purchase it – for your own protection.

On Information Available

There is more information out there on rebuilding and modifying Olds engines than could ever be placed in one document. Thus, this document focuses on stuff that we know works. If you want controversy, sign on to all the Olds (both at Wild About Cars and wherever) forums and go for it. You will get a lot of information, some BS, and lots of opinions – with no way to sort it out.

Trying to find reasonable information from multiple sources manner is like asking; “What was the best college basketball team ever?” As part of the development of Wild about Cars, we spend lots of time web surfing and believe me, we see more misinformation and opinion than facts. Please be careful with all that material – it’s not only your money but your safety as well. What we have tried to do here is use our collective experience to sort through all that stuff and come up with a logical and practical approach.

Everything in this manual will work well and reliably and make your Olds motor sing. That’s what this document is all about. You can read this and use it as a reference guide, or decide that it is toilet paper - it's your choice.

So if after reading it, you have a different opinion on what works best remember, there is still valuable information in here. With that said, we are always interested in ideas and information. So you may offer a suggestion on a revision to the manual (after all it’s virtual), by sending your comments to [email protected]. But if you do, please give us some facts to back your idea up. If it seems appropriate or reasonable, we'll include it in our updates and credit you.

This Book Covers Engine Modification Only

This Manual covers engine modification only. For Chassis and other information such as running gear and peripherals, see Oldsmobile Chassis and Running Gear Modification. The materials became too voluminous to include in one book.

Further, updates, changes and alterations regarding engines are likely to occur more frequently, making revised editions a nightmare. We hope you will bear with us and see the value in the two volume approach. We hope that by following this rout, we can keep costs down and not confuse the user.

Table of Contents

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This book contains engine modification information for the Oldsmobile Division of General Motors Corporation V-8 engines from 1964 through 1989. Earlier engines and the V-6 are covered in separate manuals.

Forward ...................................................................................................................................................... i Introduction ...................................................................................................................................... ii General ............................................................................................................................................ ii On Information Available .................................................................................................................. ii This Book Covers Engine Modification Only .................................................................................... ii

Section 01 - Preparation and Planning ............................................................................................................ 1 1.0 Thinking about your Approach......................................................................................................... 1

Introduction ..................................................................................................................................... 1 Modification Levels .......................................................................................................................... 1 What Block to Start With .................................................................................................................. 1 Begin at the Beginning .................................................................................................................... 2 First – Short Block Basics ................................................................................................................ 3 Second – The Cylinder Heads and Camshaft Basics ....................................................................... 3 Third - Induction System Basics ...................................................................................................... 4 A Note on Part Numbers ................................................................................................................. 4 A Note on NROS Parts .................................................................................................................... 4 A Note on Engine Builders .............................................................................................................. 5

1.1 Comparative Size, Dimensions & Specifications – Block versus Block ............................................ 5 1.2 Engine Identification ........................................................................................................................ 6

Identifying Engines – Small Block V-8 Engines ................................................................................ 6 The Small Block Engine - Identification at a Glance ........................................................................ 6 Identifying Engines – Big Block V-8 Engines .................................................................................... 7 The Big Block Engine - Identification at a Glance ............................................................................ 7

1.3 Key Specifications 1961-1978 V-8 Engines .................................................................................... 8 Factory Specifications - Engine ....................................................................................................... 8

Section 02 - Block Basics ............................................................................................................................. 11 2.0 Small Block ................................................................................................................................... 11

Generation 1 Cast Iron Small Block V-8 Facts .............................................................................. 11 Generation 2 Cast Iron Small Block V-8 Facts .............................................................................. 12 Generation 2 Cast Iron Diesel 260 and 350 Block Facts ............................................................... 12 Small Block Key Differences ......................................................................................................... 12

2.1 Big Block ....................................................................................................................................... 14 Generation 2 Big Block Facts ........................................................................................................ 14 Generation 2 Big Block Key Differences ....................................................................................... 15

2.2 Crankshaft Identification ................................................................................................................ 18 Crankshaft Identification – Forged Cranks ..................................................................................... 18 Flexplate ........................................................................................................................................ 18 Crankshaft Identification – Cast Cranks ......................................................................................... 19 Flexplate ........................................................................................................................................ 19

2.3 Factory Specifications V-8 Engines ............................................................................................... 20 Factory Specifications – Block Info ................................................................................................. 20 Factory Specifications – Head Info ................................................................................................. 21 Factory Specifications – Head Info Continued ............................................................................... 22 Factory Specifications – NOS Camshafts and Valve Springs ......................................................... 23 Factory Specifications – NOS Camshafts and Valve Springs Continued ....................................... 24 Factory Specifications - NROS Camshafts and Valve Springs ...................................................... 25 Factory Specifications - NROS Camshafts and Valve Springs Continued ..................................... 26

Section 03 – Building Your Short Block ......................................................................................................... 27 3.0 Some Decisions ............................................................................................................................ 27

The First Decision – What Block to Start With ................................................................................ 27 Decision Number Two - What Body is Best for a Particular Size Block ......................................... 27 Decision Three – How Much to Spend on Modification .................................................................. 28 Decision Four - Primary Use Considerations ................................................................................. 29 Decision Five – The Major Components to Use ............................................................................. 29

3.1 Camshaft Selection ....................................................................................................................... 30 Considerations .............................................................................................................................. 30 Suggested Cams ........................................................................................................................... 31 Cam and Cylinder Head Thoughts ................................................................................................ 31 Cam and Intake Manifold Thoughts ............................................................................................... 31 Cams and Vehicle Weight ............................................................................................................. 31 Cam Selection Using the Chart ..................................................................................................... 31

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Additional Cam Information ........................................................................................................... 32 Lifter Recommendations ............................................................................................................... 32 Lifter Preload ................................................................................................................................. 32 Valve Spring Selection .................................................................................................................. 32 A Note on Valve Span and Potential Valve Shrouding .................................................................. 32 Valve Span and Potential Shrouding – Standard Valve Span ........................................................ 34 Valve Span and Potential Shrouding – Maximum Valve Span ....................................................... 35 Recommended Valve Sizes .......................................................................................................... 35 Recommended Aftermarket Camshafts – by Application ............................................................... 36 Recommended Aftermarket Camshafts – by Application Continued .............................................. 37

3.2 The Build – General Rules ............................................................................................................. 38 Basic Engine Block Machining and Blueprinting Issues ................................................................ 38 Other Assembly and Machining Issues ......................................................................................... 39

3.3 Increasing Displacement ............................................................................................................... 40 Introduction – What Works ............................................................................................................. 40 Increasing Displacement on the 350 Diesel .................................................................................. 40 Increasing Displacement on the 455 ............................................................................................. 41

3.4 Suggested Builds – By Block ......................................................................................................... 41 Introduction ................................................................................................................................... 41 Suggested 260 and 307 Engine Mods........................................................................................... 42 Suggested 330 and 350 Engine Mods........................................................................................... 43 Suggested 403 Mods .................................................................................................................... 44 Suggested 400 SS and 425 Mods ................................................................................................. 45 Suggested 400 LS and 455 Mods ................................................................................................. 47 Assembly and Peripherals ............................................................................................................. 50

3.5 Block Machining and Preparation .................................................................................................. 50 Block Preparation – General .......................................................................................................... 50 Maximum Bore – by Block .............................................................................................................. 51 Specific Block Machining ............................................................................................................... 51 Engine Boring – Net Result ............................................................................................................ 54

3.6 Crankshaft, Connecting Rod and Piston Preparation .................................................................... 55 Crankshaft Preparation and Modification - All ............................................................................... 55 Crankshaft Preparation and Modification – Cast Units ................................................................... 55 Main Bearing Modification to Ensure Proper Oiling ....................................................................... 56 Manual Transmission Crankshafts ................................................................................................ 56 Connecting Rod Preparation - General ......................................................................................... 56 Rod Bolt Reuse ............................................................................................................................. 57 Rod Clearance .............................................................................................................................. 57 Connecting Rod Prep – Olds Oiling Issues .................................................................................... 57 Aftermarket Rods .......................................................................................................................... 58 Piston Preparation ......................................................................................................................... 58 Strengthening the Block Assembly ................................................................................................ 58 Engine Harmonic Balancer ............................................................................................................ 59 Completing the Short Block ........................................................................................................... 59

3.7 Special Section – Stroking the 350 Diesel and 455 ........................................................................ 60 Introduction ................................................................................................................................... 60 Stroking the 350 Diesel ................................................................................................................. 60 Stroking the 455 ............................................................................................................................ 61

3.8 Engine Oiling ................................................................................................................................. 61 Introduction ................................................................................................................................... 61 Oil Pump and Oiling System Described ........................................................................................ 61 Oil Pump Selection ........................................................................................................................ 62 Oil Pump Drive .............................................................................................................................. 62 Oil Pan Capacity and Pickup ......................................................................................................... 63 Oil Pan Selection ........................................................................................................................... 63 Crank Scrapers and Full Length Windage Trays ........................................................................... 64 Mounting the Oil Pump .................................................................................................................. 64 Oil, Oil Filter and Oil Pressure ....................................................................................................... 64

3.9 Assembling Your Short Block ........................................................................................................ 65 Installing the Crankshaft, Pistons and Connecting Rods ............................................................... 65 Installing the Cam .......................................................................................................................... 65 Checking Camshaft Retaining Bolt and Thrust Clearance ............................................................ 65 Install the lifters ............................................................................................................................. 65 Install the Cam Timing Chain and Gears ....................................................................................... 65

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The Right Timing Chain and Gears ............................................................................................... 66 A Note on Degreeing the Cam ...................................................................................................... 66 A Note on Camshaft Break-In ........................................................................................................ 66 Installing a Harmonic Balancer ...................................................................................................... 66 Scribing a New Timing Mark on the 350-455 Harmonic Balancer for the 330 V8 .......................... 67

Section 04 - Building Your Cylinder Heads .................................................................................................. 68 4.0 Picking the Correct Head ................................................................................................................. 68

Introduction ................................................................................................................................... 68 The Right Head for You ................................................................................................................. 68 Unleaded Gasoline and Cylinder Head Preparation and Use ........................................................ 68

4.1 Head Selection Criteria and Other Potential Tweaks .................................................................... 69 Introduction ................................................................................................................................... 69 Head Considerations for "Stock" Vehicles ..................................................................................... 69 Head Considerations for Factory Modified Vehicles ...................................................................... 69 Head Considerations for Street Mild Vehicles ............................................................................... 70 Head Considerations for Street Wild Vehicles ............................................................................... 70 Head Considerations for Street/Strip Vehicles .............................................................................. 70 Head Considerations for Super Modified Vehicles ........................................................................ 70 Recommended Valve Sizes .......................................................................................................... 71

4.2 Building Your Heads ...................................................................................................................... 71 Head Inspection and Preparation .................................................................................................. 71 Head Milling - General ................................................................................................................... 71 Head Milling - Detail ...................................................................................................................... 72 Calculating Compression Ratio ..................................................................................................... 72 Head Porting ................................................................................................................................. 73 Evening the Mating Surface on the Center Exhaust Ports ............................................................. 73 Sealing Off the Heat Riser Passages ............................................................................................ 73 Valve Seating and Combustion Chamber Prep ............................................................................. 74 Valve Seat Angles ......................................................................................................................... 75 Valve Guides ................................................................................................................................. 75 Valve Springs ................................................................................................................................ 75 The Relationship of Valve Length, Spring Height, Rocker Stand Height and Pushrod Length ...... 76

4.3 Checking Head Tolerances ........................................................................................................... 76 Steps to Ensure that Incorrect Valve Stem Height Does Not Occur .............................................. 76 Preventing Coil Bind and Other Interference ................................................................................. 78 Note on Coil Bind and Spring Height with Pre-1970 Heads ........................................................... 78 Mechanical Lifter Valve Clearance or “Lash” ................................................................................. 78 Setting Mechanical Lifter Valve Clearance or “Lash” ..................................................................... 78 Hydraulic Lifters and “Preload” ...................................................................................................... 78 How to Set Preload on Stock Olds Valve Train ............................................................................. 79 How to Set Hydraulic Lifter Preload ............................................................................................... 79

4.4 Assembly and Adding Performance Components ......................................................................... 80 Valves ........................................................................................................................................... 80 Rocker Arms ................................................................................................................................. 80 Pushrods ....................................................................................................................................... 81

4.4 Aftermarket Heads ........................................................................................................................ 81 Introduction ................................................................................................................................... 81 Available Aftermarket Heads ......................................................................................................... 81 Stacking Up – Head vs. Head ........................................................................................................ 83

4.5 Head Comparison Chart – Flow Figures ........................................................................................ 83 Section 05 - Fuel Delivery, Induction and Exhaust ........................................................................................ 84

5.0 Key Issues in Fuel Delivery and Induction ..................................................................................... 84 General Points .............................................................................................................................. 84 Intake Manifolds ............................................................................................................................ 84 Air Cleaners .................................................................................................................................. 85 Ram Air Tips ................................................................................................................................. 86 Carburetors - General ................................................................................................................... 87 General Carburetor Application & Usage ...................................................................................... 87 Fuel Delivery ................................................................................................................................. 88 Exhaust Headers ........................................................................................................................... 89 Exhaust System ............................................................................................................................ 90

5.1 Tuning Your Carb for Best Performance – Rochester 4GC .............................................................. 91 Rochester 4GC Carburetors – Information and General Operation ................................................ 91 Rochester 4GC Carburetors – Performance Tuning ...................................................................... 91

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5.2 Tuning Your Carb for Best Performance – Rochester 4MC & 4MV (Quadrajet) Carburetors ............ 93 Rochester 4MC and 4MV (Quadrajet) Carburetors – General Operation and Information ............. 93 Rochester 4MC and MV Carburetors – Performance Tuning and Blueprinting .............................. 95

5.3 Carter ThermoQuad Carburetor ...................................................................................................100 Carter ThermoQuad Carburetors – General Operation and Information ......................................100

5.4 Carter AFB and AVS Carburetor ..................................................................................................102 Carter AFB Carburetor .................................................................................................................102 Carter AVS Carburetor .................................................................................................................103

5.5 Other Carburetor References .......................................................................................................104 Rochester Reference ...................................................................................................................104 Carter Reference ..........................................................................................................................104 Holley Reference ..........................................................................................................................104

5.6 Carburetor Metering .....................................................................................................................104 Rochester 4G and 2G main Metering ...........................................................................................104

5.6 Carburetor Metering .....................................................................................................................105 Rochester 4M (Quadrajet) Main Metering ....................................................................................105 Rochester 4M (Quadrajet) Secondary Metering Rod Hangers ....................................................105 Rochester 4M (Quadrajet) Secondary Metering Rods ..................................................................106

Section 06 - Timing and Ignition Systems .................................................................................................. 107 6.0 Timing ..........................................................................................................................................107

Introduction ..................................................................................................................................107 Marking Your Harmonic Balancer .................................................................................................107 Balancers with Pre-set Timing Marks ...........................................................................................107 Original Ignition Settings and Considerations ...............................................................................107 Practical Ignition Advance for Unleaded Street Gasoline .............................................................108

6.1 Ignition System Upgrades ............................................................................................................109 Modifying Your Distributor ............................................................................................................109 Upgrading Your Ignition System with New Equipment .................................................................109

6.2 Spark Plug Science and Spark Plug Wires ...................................................................................110 Spark Plugs and Plug Heat Range ...............................................................................................110

Section 07 - Vendor and Other Listings ...................................................................................................... 111 7.0 Listing Central ..............................................................................................................................111

About These Listings ....................................................................................................................111 7.1 Vendor Listings ............................................................................................................................111 7.2 Photo Credits ...............................................................................................................................114

Section 08 - Assembly Worksheets & Other Key Specifications ................................................................ 116 8.0 Torque Specifications ...................................................................................................................116 8.1 Assembly Worksheet – All Blocks .................................................................................................117

How to Use These Sheets ............................................................................................................117 Section 09 - Appendix ................................................................................................................................ 124

9.0 Standard Piston Information .........................................................................................................124 9.1 Engine Bore and Stroke Compression Changes ..........................................................................124 9.2 Degreeing Your Camshaft ............................................................................................................125

Degreeing Procedures .................................................................................................................125 Calculating Actual Valve Lift .........................................................................................................125 Calculating Cam Duration ............................................................................................................125

9.3 Outside Air Induction Scoop Fitment ............................................................................................126 Introduction ..................................................................................................................................126 1966 OAI Scoop Fitment ..............................................................................................................126 1967 OAI Scoop Fitment ..............................................................................................................127 1968-1969 OAI Scoop Fitments ...................................................................................................128 1970-1972 OAI Hood/Air Cleaner Fitment ....................................................................................129

9.4 Carburetor Part Numbers .............................................................................................................130

Introduction – Preparation and Planning – Section 1

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Section 01 -

Preparation and Planning

1.0 Thinking about your Approach Introduction

Much of the Engine Section of the Manual is divided by block size. Where appropriate, we have combined the information together. As you know, the 260/307/330/350/403 cubic inch version is the “small block” and the 400/425/455 “is the big block”. Both block types are similar and can share many components, but the short blocks (block crank, rods and pistons) are different. This will be made clear in the descriptions in Section 1.2.

The original Olds Performance Manual broke the engine modifications portion into five levels of performance, and while it might seem a bit hokey by today’s standards, we will keep these designations for clarity. Suffice it to say; only the first two levels have any chance of passing today’s sniff tests. If you live in states where you car has to pass emission control testing, be very careful when modifying you engine.

Modification Levels

We will use six levels of performance improvement in this Manual:

Stock. Back in the day, stock was a pretty loose term, so we include it and tell you what you can get away with if you are looking to tweak your rare, restored Olds without running afoul of car show judges.

Factory High Performance. Factory High Performance is bringing you engine up to the best specifications that your engine block would have experienced in 1969 – 1971 - as if it had been equipped as a “W” Code car. These cars were optimized for horsepower and with drag racing in mind1.

Street Mild. Street Mild takes what the Factory learned and then tweaks it with some aftermarket and tuning tricks the boys in Lansing weren’t allowed to do.

Street Wild. A Street Wild car will not likely pass any state’s sniff test, and unless your spouse or significant other is a gear head, they will not like riding around in your Olds – but you definitely will.

Street/Strip. A Street/Strip car is a drag or road race car that you will barely be able to drive to the event, but when you get there – hang on!

Super Modified. Get a trailer.

Our theory in Section 3, Engine Block, is to build a bullet proof block that can be used in any level of performance –

1 Since most of you will not have any or only rudimentary computer

controls on your 1964 – 1989 Olds, we can take advantage of what worked in the 1960s and early ‘70s and before the computer was used as an engine tuning tool. However adding modern port fuel injection and computer controls are discussed in Section 5 of this Manual.

from Stock to Super Modified (with compression ratio as the only issue). Thus, you can move up through the performance levels without pulling your engine or dropping pieces in the road. Our theory is that most of you will want to enhance the performance of your Olds over time, and if you have a good foundation, you won’t have to go back to square one. The idea is that you can build up from Stock to Street/Strip without changing out the short block2. A Super Modified engine should be built from scratch, but if you did want to go there, your properly prepared block could be used.

What Block to Start With

This is discussed in detail in Section 3, but the premise in this Manual is that you are starting your build from the ground up, and not just making some tweaks to your existing engine, though you can use the information to do so. But when building a high performance engine, you will obviously get the best performance per cubic inch when you modify an engine that can respond best to the increased loads, rpm and other aspects that produce horsepower.

And it’s all about “bang for the buck” when modifying an engine. While many of these suggestions will work on any Olds engine, some blocks are better than others when it comes to strength and reliability, and others are limited by the size they can be brought out to or are limited in availability of high performance parts.

For example, the small block cannot support more than 380 cubic inches and still have a bullet proof lower end. The 403 is an iffy choice for a true high performance engine because of its "windowed" main webs3. And the long stroke 400, the 260, and 307 have bore sizes which shroud the intake valve.

These engines can all make horsepower, but, at some point, they will become a liability if further modification is sought, or they will be unable to make the horsepower you may need. So if you are seeking a certain level of power or you have a certain performance level in mind, don't limit yourself or reach a development dead end by starting with the wrong block.

Consider:

Getting more than 200 HP from the 260 requires as much expense as getting 350 HP from a 330/350.

A 307 will not stay intact if you want to consistently rev it past 5500 rpm, whereas a 330/350 will handle 1000 rpm past that all day long.

A 403 is a good street (moderate rpm) engine, but not a race engine. It will fail in high rpm trim. Though the

2 This doesn’t mean that you may not have to replace other

components such as cam, heads etc. if you do move up in levels of performance. However, you initial investment will not need to be undone.

3 See Section 2, Small Block Facts for more information.


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valve train will sustain 7500, the lower end will consistently fail at anything over 5500.

A long stroke 400 will never make the same HP as a short stroke 400 and live.

A 425 can take more rpms than a 455, but the 455 will always out torque it.

So pick what your HP intentions are, what chassis the engine will sit in (see below for suggestions), and what your budget is, and then start work. If you have a 260 in your Cutlass and want more than spirited performance, remove it and install a 330 – 403. If you are going racing, use a 330/350 or a big block. If you have a 1978 Delta 88 with a 403 and want a good cruiser, the 403 is a great engine to use, but if you are looking for 400 hp, you can get there, but eventually you will break the motor. If you are running a 1968 442, and want it to surprise GTOs, we have a solution for you, but if you are going bracket racing, get a 425/455. Get the idea?

Last, remember that the chassis and driveline will likely have to be modified if you add a 50% or more increase in HP and torque. Clutches, auto transmissions, rear ends etc were usually designed to handle only a certain level of power. This is less true in the 60s and early 70s cars, where they anticipated a broad range of engine sizes being installed in the cars, but from about 1976 on, most of the running gear is marginal when any power increase is forthcoming. See Chassis – Running Gear Modification and Tuning Guide (published separately) for more info.

Begin at the Beginning

Too many people modify their engine without a plan. This costs much, much more than if you get out a pencil (or use your PC) and plan out what you are trying to do and what it’s likely to cost. The best advice?

1. Decide what engine block family and size you want to start with right away. Most people start out modifying the engine that came in the car, and then realize that it didn’t fit their needs and trash it and start over. Obviously, this is an expensive way to go, but almost every gearhead has done this, not once, but a few times. Ask knowledgeable people and they will tell you dozens of stories about this mistake.

Here are some basic guidelines to assist you in the start up decision:

RPM: If you are looking to make horsepower from twisting the engine, use a 330/350. The 330 and 350 will take the most abuse in this regard. Late 307s 350s, and 403s have “windows” in the main bearing webs that can cause crank failure above 5500 rpm. It has been said that there were 403s cast without these windows for Buick and Pontiac wagons with the towing package, but our staff have never seen one.

TORQUE: If you want tree-stump pulling torque, go for the big block. People have said that the big block will not fit in the later (1979-1987) bodies, but since it is only 1 – 1 ½ inches wider, the staff is not convinced. If it will not fit, use a 403. Remember, it is TORQUE that launches the car and HP that moves it along. In the 60’s and 70’s we had an adage: “On the street, torque talks”. Remember

that Oldsmobile chassis are not lightweights (unless you are stuffing something in an X or H body). Street cars like torque, race cars like BOTH.

HORSEPOWER: All blocks can be made to make copious HP. The questions are: 1) how much is it going to cost per dollar; and 2) where in the RPM band do you want the HP. If two engines both develop a max HP of 400, but one does it @ 5000 RPM and the other @ 7000 RPM, the one at lower RPM will obviously be easier to drive and use.

FLAT HP and TORQUE CURVES: Engines that have a fairly sharp rise in HP which stays at that level over a long period will – on the street – be generally quicker than one with higher HP, but delivered in a short RPM band. The same is true for engines with a flat torque curve. Peaky engines look great on the dyno, but need tons of gear and eat gas, which at close to $4.00 a gallon, is not fun anymore.

COST: Generally, an engine with more cubes that turns lower RPM will cost less to build and maintain than a smaller engine that needs to rev to make HP. A larger engine with the proper building foundation can always be modified to deliver more HP. A smaller engine will be maxed out faster.

2. Decide what the car's primary use. Street only? Occasional trips to the strip? Trailer only? Decide as soon as possible. Remember, a 1975 442 with a 350 is not going to be a good strip car unless you have the money of Donald Trump or Bill Gates. A 1975 Omega with that 350 would be a much better choice.

3. Recognize what body size the engine will be installed in. When all is said and done, the engine has to move weight. Thus, if you are starting out with a specific body4 or you are considering an Olds but don’t have a preference, here are our suggestions – by year. 1964 – 1972 A body: #1 = 425 (street and racing); #2

= 350 (street) 1965 – 1967 Starfire: #1 = 425 (street and racing) 1965 – 1977 B and C Body: #1 = 425; # 2 = 455

(street only – don’t take the big body racing - please) 1973 – 1977 A Body: #1 = 425 and # 2 = 455 (street

and racing); #3 = 403 (street) 1973 – 1981 X Body: #1 = 350 and #2 = 403 (street);

#3 = 425 (racing – the BB will fit) 1976 – 1980 H Body: #1 = 350 (street); #2 = 4035

(racing) - will require motor mount fabrication, but will fit.

1978 – 1987 A Body: #1 = 307; #2 = 350 (street); #3 = 4034 (racing)

4. Decide how much money you are likely to spend. Remember, that you will likely spend double of whatever you decide, even if your plan. So do some research on costs of parts, labor and incidentals - and

4 Body designations/descriptions are found in the Chassis and

Service Manual for the appropriate year. 5 The 350 diesel block can be substituted for Street Strip or Super

Modified. See Engine Section.


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where possible, get quotes or written estimates. Then make up a budget and try like heck to stick to it. Your wallet (and any significant other) will thank you. There is a worksheet in the Section 8 that will help.

5. Don’t forget the chassis. It’s not as bad now as in the 60s and 70s, but most people still put most of their hard-earned dollars in the engine, and are disappointed when the car handles like a whale or cannot get the power down on the strip. Remember Rules 1 - 4 above, and include chassis and brake modifications or at least simple restoration of the suspension pieces in your plan Do not forget to add this pricing to your estimate. Use the worksheet in Section 8.

6. Find out if the parts you are looking for are readily available. We have repeatedly seen people base their entire project build on a part that is so rare that even the entire engineering division at Oldsmobile has never heard of it. (Like 455 blocks with 4-bolt main bearing supports - of which there is no known example). Use the worksheet in the Section 8.

7. Decide if there is enough information available on what you are trying to do. Again, like parts that are not available, the same can be said for information. Use the worksheet in the Section 8.

8. Decide on what you have the skills to do and where you will need professional help. Rule One: If you can’t do it yourself, it will cost you about $300 per hour. Rule Two: See Rule One. Some things take special tools, skills and machinery that few have in their garage; and some things are just too sophisticated for most of hobbyists to do. Be honest with yourself on this. Use the worksheet in the Section 8.

9. The myth of high compression as a major factor in HP. This myth is especially true with today’s pump gas. Engines with 8.5 – 9.5:1 are best for the fuel we have now, so unless you are building a Street/Strip or Super-Modified engine, try to stay in that CR ball park. Since most of the cars we are talking about in this Manual do not have computer controls, you will be able to run more ignition advance with a lower compression motor. Even HE ignitions will give better fuel flame burn at lower compression. These factors are far more important for HP and torque than CR.

10. Always build the best short block you can. After you’ve made all the decisions on 1-9 above, and unless you are merely tweaking your current engine just to be perky, make Step One building a new short block.

First – Short Block Basics

Here are our suggestions:

Start Fresh. Build a new short block from another block while your car is still running. That way you can get it right without pulling out your current engine. This will save the aggravation of having a lot of down time as well. If you are restoring a car, then you may have no choice if you want matching numbers, etc. We do not recommend "fooling" judges, and if you are doing a 100 point restoration, you should err on the side of authenticity and only make mods that would have or could have been done in the year of your vehicle, building a bullet-proof block to run on the fuel we have now can be

done (like adding forged instead of cast pistons). If you are restoring your Olds, this Manual will tell you how to do that and what proper NOS or NROS parts should be used. But if you are looking to build a "sleeper", remember that many Oldsmobiles do not have the serial number on the block and heads and merely need the proper casting number and the ID stamp (or tape) on the oil filler tube. This means you can pull the tube out of your old block and insert it in the new one. Remember that tip we gave you on collecting information? Be sure to check it out first. There are a ton of 1968 – 1969 442s running around with 455s in them and no one is the wiser.

Use the Best Parts. Employ the best possible parts in the rotating assembly (crank, rods and pistons). We always suggest forged pistons and crank, regardless of the application. There are good aftermarket connecting rods available, but the 350 and 400SS/425 and even the late 400/455 rods will not fail in a street engine unless you are using a blower6.

Get the Best Machine Shop. Find the best machinist your money can buy to do your work. Make sure to be honest about what the engine will be used for when talking with the builder. Street engines need different clearances than racing engines. Regardless, there is a difference between a standard rebuild and a performance rebuild.7

All engine blocks should be checked for cracks and damage before you use them (most quality engine builders will do this as part of the build). Balance the assembly as if it were a race engine, regardless of the application. Prep the short block as if it was going to be on display at the Pebble Beach Concours. Clean, then clean again, debur, polish - and even paint it with the proper type of paint.

Second – The Cylinder Heads and Camshaft Basics

Work on cylinder heads next. It may surprise you that what heads you use will affect the engine’s power more than the intake and exhaust manifolds slapped on those heads. Obviously they should all work together, but a fancy intake manifold attached to a lousy set of heads will do worse than a lousy manifold attached to a good set of heads. Here are some tips:

Make your cylinder head decision based upon money available and your intended use of the car. Rule One: Most street engines will be fine with a well prepared and proper set of factory heads. Rule Two: See Rule One.

Treat your head rebuild just as you will treat your block rebuild. Find the best machinist your money can buy to do

6 Small block: 1964-67 330 forged crank. Big block: 1965-67 400

or 425 forged crank. See Block ID section. 7 See Section 03 in this Manual for specs.

A solid, well prepped short block can add 10-15% to your HP and TORQUE with no other changes – that’s 30 to 45

HP on a 300 HP engine.

Think about where your money ought to go first.


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your heads8. Even stock heads can benefit from great machining and race level prep. Again, use quality parts. W-31 and 442 valve sizes are adequate for most applications other than race only engines. (See Section 04 – Building Your Cylinder Heads).

Stay away from exotic rocker arm assemblies in Stock and Factory Modified engines. Roller rocker assemblies and different rocker ratios should be your last effort to extract more horsepower; and they can be added later. Roller rocker assemblies will free up some horsepower due to less rotational friction and more accurate valve opening. And different rocker ratios will open the cam more, but they deliver less HP per dollar than other mods.

Get the car to make its maximum HP first, and then consider adding these pieces. Remember, these items sit on the most accessible part of the engine so they are easy to do later. This does not mean you shouldn’t consider adjustable rockers or pushrods. (See Section 04 – Building Your Cylinder Heads).

Decide on what camshaft you want – then back off from that spec a bit. Almost none of you will listen to this advice, but the biggest mistake we see is over-cammed engines9. Most of the cam manufacturers give out good information on what will work best for your application – please pay attention. Match the valve springs to the cam and to the engine’s useable RPM range.

Third - Induction System Basics

Match the induction system to the car’s primary use. Just like the cam, induction systems can hurt the car as much as than help. Engines designed for torque do not want or respond to race type manifolds - or too much carburetor. Do not apply More’s Law here; (if some is good, more is better).

Most aftermarket single plane, single 4 barrel carb manifolds will produce better results than ALL stock factory manifolds, even for street use. That said; if you have to scrimp anywhere, scrimp here and use a factory 4 barrel manifold. Here are some recommendations:

Small Block Engines: The factory aluminum W-31 4 bbl manifold is best, next is the 1968-1969 4 barrel cast iron pieces, if you are running a Quadrajet. All earlier Rochester 4GC and Carter and AFB manifolds can be machined out to accept the largest CFM model carbs. If you need to use an EGR manifold, go aftermarket, otherwise a 1973 or 74 manifold is the best bet. See the chart in Section 05.

Big Block Engines: if you are running a Quadrajet, the stock manifolds used in the period 1967 through 1970 will work fine in all street, non-race engines. Earlier 400 and 425s can use their stock manifold. All earlier Rochester 4GC and Carter and AFB manifolds can be machined out to accept the largest CFM model carbs. If you need to use an EGR manifold, go aftermarket, otherwise a

8 The machinist doing the heads does not have to be the one doing

the block. Consider experience in building and porting Olds heads as a major factor.

9 As an example, the factory supplied the 328 cam to 1968 – 1971 stick W-30’s (figuring the cars would end up on the strip). On the street this cam was too much. When both cars ran the stock 3.90 rear, the auto car, with a 285/287 cam, would smoke the stick car in stock trim.

1973/74 manifold is the best bet. See the chart in Section 05.

A Note on Part Numbers

The difficulty with the General Motors parts numbering system is that parts were and are withdrawn from service and replaced with others - and then listed as the proper part, but many times the specs are not the same as the original. Worse, the original number is then removed in from the system as “no longer available”.

Further, in the late 1970s GM consolidated their parts system and began issuing part numbers that are consistent across the entire line of brands. (Originally, each brand had their own set of part numbers). At the time of this consolidation the parts warehouse in Lansing was effectively “closed” and many of the “W” code parts were sold as scrap (including almost all of the W-31 and W-30 aluminum manifolds)! Last, Oldsmobile is no longer in business, so some parts will not be able to be found in the GM inventory as they were scrapped out according to the US auto industry’s “10 year” rule.

The parts numbers found in this manual are as much as possible the original numbers from the 60s through the 80s. Our rationale is that when one is either looking for NOS (New Old Stock) or NROS (New Remanufactured Old Stock) parts, these numbers will either be on the original box or what the NROS manufacturer will use for reference. In most cases, you can more easily make a relationship between the original number and any replacement part. We have also noted where a later part number can be used as a replacement without affecting performance (this especially applies to cams and valve train).

A list of key part numbers and ID information is found in Appendices A, B and C. Good hunting.

A Note on NROS Parts

The NROS (New Replacement of Stock) market is in full swing. The only problem is that there may be issues of quality in that many of the NROS parts are made off-shore. Some parts have an even higher level of attention paid to them than the original, regardless of their origin, due to advances in metallurgy and machining. My advice is to purchase these NROS parts from reputable businesses that have been around for a while and have proven their customer relationships.

Three NROS vendors that we can highly recommend are as follows:

First is Fusick Automotive Products www.fusick.com. Mike Fusick has many rare and almost impossible to find body, chrome and accessories available and ready to ship.

Next is Supercars Unlimited. Greg Rollin has stuck with delivering high quality engine parts for Oldsmobiles for almost 20 years. www.supercarsunlimited.com He has cams and other NROS parts that just can't be found anywhere else.

Last, but not least, is Year One, www.yearone.com, who has been in business since the early 80s and who jumped into the NROS business when it was hardly profitable, and who has grown to a legitimate giant in the NROS industry.


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We owe a lot of the availability of NROS parts to the boys at Fusick, Supercars Unlimited and Year One. A complete listing of NROS and aftermarket dealers is found in Section 07.

A Note on Engine Builders

There are a lot of great engine builders out there, and one might be in your local neighborhood, but if you are looking for an engine builder who has been modifying and building hugely successful Oldsmobile engines since the 1980's there is only one I can now truly recommend, based upon numerous complaints on Mondello, and that is Dick Miller Racing, www.dickmillerracing.com (662) 233-2301.

Dick is a veteran racer turned engine builder and has forgotten more than what most others know about Olds engines So if you need a part or advice, contact Dick. We

can truly say that without guys like Dick, Olds performance would not be the same.

Mondello cams, rocker assemblies and oiling products are still OK, but where you can go to the original source for a product, such as pistons and the like, do so.

1.1 Comparative Size, Dimensions & Specifications – Block versus Block This Section will describe the various modern Oldsmobile engines, beginning with the 1964 330 V-8, including all big blocks and ending with the 307 V-8. Below is a picture and chart showing the size and weight of the various last generation pushrod Oldsmobile V8 engines.

The dimensions are for comparative purposes only. Measurements and weights provided by the manufacturer and many not take into account valve cover redesign, exhaust headers, water pump size, and accessories, etc.


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1.2 Engine Identification The best way to identify a particular engine is by casting number. However, one needs to be able to cut down the odds by using some visual clues. The following Section will help you with this process. Use the Casting Numbers Chart(s) at the end of this Section for a more accurate breakdown.

Identifying Engines – Small Block V-8 Engines

Olds used the knowledge from the development of their 215 Aluminum engine10 to design a small block V-8 cast in iron which became the famous 260-403 series engine. This was the second GM engine to use "thin wall" casting processes, with the Buick 300-340 being the first. The thin wall process helped to keep the engine weight down to just over 550 lbs. This was about 50-150 pounds less than comparably sized engines being produced at that time (the Chevy small block weighed about 575 lbs and was considered a lightweight).

Cylinder head design was taken from what had been learned in the 215 program, with the rocker arms initially using a shaft. In mid-year 1964, the heads were changed to the unique Olds stamped steel rockers riding on an aluminum pedestal for the valves for that cylinder, which resulted in a lightweight setup that allowed more rpms with lower valve spring pressure.

Like the 215, the small block used a significant "over square" design, with the bore at 3.9385" and a stroke of 3.385”, resulting in 330 cubic inches. Later 350 and 403 engines used larger bores, with the 350 using a 4.057" bore and the 403 using a huge 4.351" bore which required siamesed bore coring.

The 260 and 307 went in the other direction, still retaining the 3.385" stroke, but reducing the bore to 3.500" and 3.800" respectively. Even so, both engines were still over square. They utilized the same tooling for their cylinder heads, which resulted in much smaller intake valves, because of the potential for valve shrouding resultant from the smaller cylinder bores,

Regardless, the small block engine was quite successful, being placed in over 2.5 million vehicles including each and every GM make, and having been produced for over 25 years.

10 See Book Two of the Engine Modification and Tuning Guide for a

complete history and modification information on the 215 engine. A history of production and models which used the 215 is found in Oldsmobile Technical Data Sheet, published by Wild About Cars.

The Small Block Engine - Identification at a Glance

All Small Blocks will have a deck height of 9.330". All small block engines have the distributor at the rear and the starter on the left side.

260 V8s at a Glance - The 260 can be found in all Cutlasses, (A-Body and G-Body) from 1975–1981. For 1975 and 1978 engines, the casting code "2A" will be found next to the oil filler tube; for 1977-1981 engines, the casting code "2B" will be found next to the oil filler tube.

307 V8s at a Glance - The 307 can be found in all Cutlasses, (G-Body) from 1980 – 1989. For these engines, the casting code "5A" will be found next to the oil filler tube. Some 307s are marked "5.0 L" or "5L" on the side of the block near the motor mount stud holes.

330 V8s at a Glance – The 330 can be found in all Cutlasses, (A-Body) from 1964–1967 and in (B-Body) Jetstar 88s from 1965-1967. For 1964-1966 engines, the casting code "1" or "1A" (45 lifter angle) will be found next to the oil filler tube; for 1967 engines, the casting code "3" will be found next to the oil filler tube.

350 V8s at a Glance – The 350 can be found in all Cutlasses, (A-Body) from 1968–1976 and in some (B-Body) Delta 88s from 1968-1976. For 1968-1973 engines, the casting code "2" will be found next to the oil filler tube; for 1974-1976 engines, the casting code "5" will be found next to the oil filler tube; for 1977-1980 engines, the casting code "3B" will be found next to the oil filler tube, for 1979-1980 350 H/O engines "3A" will be found next to the oil filler tube. The 350s produced with the 3B code will have "windows" in the main saddles and are inappropriate for any high performance modification.

350 Diesel V8s at a Glance - The diesel 350 can be found in some Delta 88s (B-Body), 98s (C-Body) and some Toronados from 1977-1981, as well as Pontiacs, Buicks and Cadillacs. For these engines, the casting code "D3" will be found next to the oil filler tube and the cylinder heads will be marked with "D3A". These blocks are unique to diesel engines but can be used as gasoline engines, once modified. They have main bearing journals that replicate the big block engines at 3.000”. Diesels came in 260 cu. in. versions ("D2"), but they can usually be bored safely to 350 specs.

403 V8s at a Glance - The 403 was used in Delta 88s, 98s and Toronados in the period 1977–1979. It was a very popular block and used by Pontiac in its Trans Am during that period. For 1977 engines, the casting code "4A" will be found next to the oil filler tube; for 1978-1979, the casting code "4B" will be found next to the oil filler tube. 403s are marked "403" on the side of the block, near the motor mount stud holes. All 403s will have cylinder heads marked "4A" near the number 1 spark plug.

Use the Casting Numbers Chart(s) in Section 2.3 for a more accurate breakdown.

330-403 V-8. This picture shows the 330 in a 1964 442. Note that the distributor is rear mounted, in the traditional Oldsmobile manner.


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Identifying Engines – Big Block V-8 Engines

Like the Oldsmobile small block, the big block drew its roots from the 215 program. Essentially, it was an expanded version of the 330, with the same bore centers and even crankshaft spacing. As such, and unlike any other GM engine, the big and small block can share heads, cams, cranks (with modification) and almost every other ancillary component.

This makes the Olds engine very versatile as many components designed for different applications, blocks and even series (including the diesel) can be swapped into almost all of the blocks.

The first iterations of the big block were released in 1965 in both 400 and 425 cubic inch configurations. The 400 was almost a "square" design with a bore of 4.000" and a stroke of 3.975". This iteration led to good torque and great horsepower, with the engines rated at 350 hp and 440 ft. lbs. of torque. Fitted to the Cutlass as the "442", it gave the muscle car parity with the GTO, its major rival.

The 425 was a big car engine, found in the Delta 88, Starfire and the 98. With a bore of 4.125" and the same 3.975" stroke, it produced 375 hp and 475 ft. lbs of torque. Both engines revved well due to their lightweight valve train and did not break under abuse. In1968, the engine grew to 455 cubic inches via a stroke increase to 4.250". The 442 had to make do with a "de-bored" 455 (at 3.870"). This engine did not fare well as the smaller bore shrouded the intake valve and the extra long stroke resulted in many a spun bearing when revved as the earlier 400 had been.

Big blocks were produced until 1976 and are quite plentiful, as they were the mainstay of the Olds fleet for over ten years – at a time when Olds production was at its highest.

The Big Block Engine - Identification at a Glance

The Big Block should have a deck height of 10.625".11 All big block engines have the distributor at the rear and the starter on the left side.

400 Short Stroke V8s at a Glance - The 400 short stroke engines can be found in all A-Body 442 and Cutlass Turnpike Cruisers (which used a 2 barrel carb) from 1965–1967. For 1965 engines, the casting code "B" will be found next to the oil filler tube; for 1966-19677 engines, the casting code "E" will be found next to the oil filler tube.

400 Long Stroke V8s at a Glance - The 400 long stroke engines can be found in all A-Body 442 and Cutlass Turnpike Cruisers (which used a 2 barrel carb) from 1968–1969. For these engines, the casting code "G" will be found next to the oil filler tube. While these engines do have the same stroke as the 455, they cannot be bored to the 4.125" bore of the bigger block.

425 V8s at a Glance – The 425 engines can be found in some Delta 88s and all Starfires (B-Body), all 98s (C-Body) from 1965–1967, and all Toronados from 1966-1967. For 1965 engines, the casting code "A" will be found next to the oil filler tube; for 1966-1967 engines, the casting code "C" or "D" will be found next to the oil filler tube.

455 V8s at a Glance - The 455 can be found in some Delta 88s (B-Body), all 98s (C-Body) from 1968–1976 and all Toronados from 1968-1976, and also be found in all 442s (A-Body) and some Cutlass Supremes from 1970-1975. For 1968-1974 engines (1973-1974 442s), the casting code "F" will be found next to the oil filler tube. For 1973-1976 engines, the casting code "FA" or "FA" will be found next to the oil filler tube. On late 1976 engines, the casting code "L" will be found next to the oil filler tube.

Use the Casting Numbers Chart(s) in Section 2.3 for a more accurate breakdown.

11 Deck height can be measured from the crank centerline to the top

of the block in line with the center of the piston bore. This can be measured at the engine front.

400-455 V-8 compared to the 330-350 V-8. Note cast rib on front of the big block, absent on the small block. Except for deck height & main bearing

journal size, the blocks are identical in all other dimensions.

400-455 V-8 330-350 V-8

The casting # can be found opposite the hole that accepts the oil filler tube at the front of the block. The "A" casting code shown here identifies this as the first offered 400-425 block with the 45 lifter angle (this block was machined

to a 4.000" or 4.125" bore, as needed).

Oil filler hole


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1.3 Key Specifications 1961-1978 V-8 Engines Factory Specifications - Engine

Engine factory specifications, especially when it comes to horsepower and torque, are usually overly optimistic. Olds, however, seemed to be accurate in its listings, likely because its engines produced good figures in the first place. Buick, Oldsmobile and Cadillac seemed to stress torque once they were able to claim at least 300 hp, whereas Chevy and Pontiac always tended to show higher and higher horsepower outputs.

The following specifications are based upon published reports, factory brochures and service manuals, factory updates, and factory technical bulletins. Where ambiguity resulted, we have chosen what appears to be the most common specification. If you have information that may counter what is published here, you may send it to the manual editors at [email protected] .

Tune-up specs may be found in Section 9 - Appendix.


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Block Basics – Section 2

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Section 02 -

Block Basics

2.0 Small Block

Generation 1 Cast Iron Small Block V-8 Facts

General. In 1964 Olds replaced their small block 215 V8 with a cast iron block of completely new design. The 330 V-8 shared none of its engine block architecture with that of the 215 V-8 and the 225 V-6 sourced from Buick. The engine was no longer aluminum, but cast iron, as weight became less of a factor with the engine going into both the larger mid-sized F-85s, Cutlasses and the full-size Jetstars introduced in that year. The engine was designed as a replacement for the 215, but was cast iron and enlarged in anticipation of the growth in size of the mid-size cars, where it was to be primarily used and as the workhorse for the entry-level full sized vehicles. Horsepower and torque for the 330 allowed for the engine to be installed in the full-sized Jetstars as the base engine and in 4-barrel form as the upscale powerplant. In 1968 the engine was enlarged to 350 cubic inches and used in 2-barrel and 4-barrel form.

This engine was offered from 1964 through 1975, when it was replaced by the Generation 2 small block. This engine was offered in five flavors with displacements from 260 to 403 cubic inches. (See below).

Not So Thin Wall Casting. The 330/350 small block was designed to be a “thin wall’ cast design, but because casting cores did not have the technology we do today, Olds built a little extra in the walls of the early blocks. Thus, blocks from 1964 to 1977 can easily be bored to 0.060”. All 330s can come out to the equivalent to a 0.060” over 350 which, for the 330 is 0.1815” over. We have seen 330/350s taken out to be able to take a 425 piston (4.125”), but the block should be sonic tested first. Frankly, the largest all this boring is going to do is take your small block to 360 cubic inches, a big gain in a 330, but only 10 cu. in. in a 350. If you are looking for more cubes – go to the big block. In our opinion, except for the 330, over boring should only be used to clean up the bores.

330 & 350 Block Key Differences. The key differences between the 330 and 350 are the 350’s larger bore and the 330’s forged crank.

1964 – 1966 Valve Lifter Angle. All 1964–1966 blocks used a different valve lifter angle of attack on the cam (45). Thus 1964–1966 330 blocks CANNOT USE 1967 AND LATER CAMS. All 1964–1966 cams WILL NOT WORK in 1967 and later blocks. Later blocks used a 39 lifter angle. Blocks with a “1” or “1A” cast up near the oil filler tube used the 45 lifter angle and should be avoided, if possible.

Early 330 Rocker Arms. The first run of 330 blocks was equipped with rocker arms similar to the previous 394 block that traces its heritage back to 1949. These rockers had a shaft that ran the entire length of the head to which the rockers were attached, similar to the Aluminum 215 and Buick engines. This is a very stable setup, but it weighs more and was more expensive to manufacture than the stamped steel rockers that are common on a 1965-1989 Olds. 1964 engines up to the engine serial number 034275 have these heads and should be avoided where possible.

Bore/Stroke. The small block does have the advantage of an excellent bore/stroke ratio and nice, easy to oil, main bearing sizes. As such it will rev to 6500 without spinning bearings if proper oiling is used. It makes more than enough torque for "A", "X" and "G" body performance.

Bearing Diameter. The small block uses bearing sizes similar to small block Chevys and thus has less bearing surface to oil, important as the engine rpms rise. The connecting rod journal size is 2.125”; the main journal size is 2.5000”.

Crankshaft. The 330 used a forged crankshaft and all others did not. The forged crank will take more abuse, however the cast nodular iron crank in the early 350 seems to hold up well in performance work. Significant in the forged versus cast crank is that the 330 uses a different flywheel bolt pattern than the 350. Thus, 330 flywheels and flexplates are only available in junkyards or from suppliers like Mondello and ATI. If you are scrounging a 330 block for the crank, take the flexplate too. (See the enclosed chart for the appropriate parts numbers).

Pistons. Pistons in all 260 through 403 engines (except the diesel) are cast, and use the same construction. As such, they have the same pin position/size, with only the piston bore as different. This allows overbored 330s to accept stock or aftermarket 350 pistons. However, the 330-350 blocks cannot be overbored to accept Generation 2 403 pistons, since the 403 block is siamesed. 350 diesel pistons are of a different construction and pin size.

Shared Components with the Big Block. The small block engine shared many of the components of the 400/425 big block that would be introduced a year later. This included the camshaft, rocker arms and springs, the cam bearings, the distributor, the starter, oil pan and front cover and water

The famous “Ram Rod 350” – the 1968 W-31 package. The air scoops fit under the bumper. It was also offered in 1969.

(This system was used on the 400 W-30 and W-32 as well).

Block Basics – Section 2

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pump. The cylinder heads will bolt on, but they contain much larger ports and valves, and in most cases, these components hurt low-end performance (see W-31 engine option, below). With machining, the cranks could be interchanged as they are the same length, (the 330/350 utilizes 2.12" rod journals versus 2.50"; and 2.50" mains versus 3.00"), but there is little reason to do so as it is far more appropriate to select the block for the engine size desired. A 403 with the 3.975" 455 crank would be 480 cu. in. with a 0.030" overbore, however. Interesting.

Generation 2 Cast Iron Small Block V-8 Facts

General. This engine though so similar to the previous original 330-350 in size and block design, is considered a Generation 3 engine because of its "windowed" main bearing webs. This change is found in all the 260, 307 and 403 designs and the 350s constructed after 1976. All small blocks after 1976, including the diesel, used ½" head bolts rather than 7/16".

Thin Wall Casting. This block is truly thin wall cast, and weighs as much as 25 lbs less than 1964-1976 engines. None of these blocks should be overbored more than 0.030".

Windowed Mains. From 1977 onward all small blocks, including the 403 were produced with “windows” in the main bearing journal area, which obviously affects strength and longevity under hard use. (Diesel blocks are an exception). For 403 owners, there are rumors of solid main journal 403's, cast using the pre-1977 technique. Supposedly 2500 solid main 403's were produced in 1977 - used in the large Buick and Olds wagons. A solid main journal 403 can be determined by looking at the block casting number. 403 Block Casting Numbers: 557265-4A, 553990-4A, and 554990-4A are supposed to have no “windows”. With only 2500 produced, these are a rare but beneficial find.

Generation 2 Cast Iron Diesel 260 and 350 Block Facts

Diesel blocks. The diesel can be identified by a large “DX” cast right above the right hand center freeze plug and "D2" (260) and “D3” (350) by the oil fill tube. Diesel blocks are quite hefty, with 0.75” wide main bearing webs, 455 main bearing journal sizes (which have a diameter of 3.0003” rather than 2.4985”); hence they run 455 main bearing caps. They also have extra heft on all stressed areas, including the cylinder walls and the block deck. This block can be bored to 4.125” easily. Know that Olds big blocks and diesels send too much oil to the lifters, so if you intend to use this block (good for supercharged, road race, and nitrous applications), see Section 3.

Small Block Key Differences

Modifications to these engines will be covered in later sections.

Block. There are some significant differences between the small block engines. All 330 through 403 blocks use the same 9.330" deck height.

The 260: The 260 was designed and built to provide engines for Olds A and G body vehicles without relying on other GM divisions for a small, fuel efficient engine

supply and so as to use existing tooling. (Olds was the largest selling GM brand at the time). It was superseded by the 307 in 1982. Its small 3.495" bore, but standard small block 3.385" stroke kept it over square, but severely restricted the intake valve size and resulted in poor combustion chamber swirl12. Contrary to expectations, it was a very inefficient engine at a time when fuel efficiency was paramount. The 260 did not come with a 4 bbl manifold. 307 heads and intakes can be fitted, but the bores will have to be notched on the intake side.

The 307: The 307 was the last Olds V8. It was actually quite a good engine, and with the right parts can make excellent HP. It is a true 5.0 Liter engine, with a bore of 3.800" and the 3.385" stroke. Its "windowed" main journals are its weak point. If you are looking for big horsepower from a small block, utilize a 330-350. 330 and 350 heads can be fitted, but the cylinder bores will likely need to be notched for intake valve clearance, especially if the W-31 style 2.00" (or larger) valves are installed.

The 330: The 330 was the first "thin wall" cast Olds block. It came in two flavors: an early 45 lifter angle block and a 39 lifter angle block which was common to all later Olds engines. The 45 lifter angle block requires special camshafts and is not recommended, though if you are restoring a 1964-1966 Cutlass, cams are available for this engine. (The original 1964 442 did utilize this block). The 330 followed the Aluminum 215's "under square" practice, with a bore larger than stroke at 3.9385" x 3.385". The 330 and 350 share many common pieces, except for the crank, which is forged in the 330. This requires a different flywheel/flexplate. The 1964-1966 330 also used an intake, in 4 bbl mode that was machined for a Rochester 4GC carb rather than a Quadrajet. The later 350 Quadrajet manifold will fit. 330s will take a 0.060" overbore safely and can usually be bored to accept

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Engine Modification and Tuning Guide Coverwildaboutcarsonline.com/members/AardvarkPublisher... · 2016. 3. 7. · Engine Modification and Tuning Guide Oldsmobile Gen 2 V-8 Engines