— Todd Ryden, Contributing Editor
INTRODUCTION
Most folks feel they don’t need an introduction to small-block Chevy V-8 engines. So many people have grown up driving, building, or racing one, that the engine seems very familiar. The most-popular and best-designed automotive engine is still around after six decades of service. More than 60 million small-blocks have been produced and millions of words have been written about how to build them.
In the late 1980s, the small-block changed. And it did one more time in the mid-1990s. The Generation I family of motors we know so well has been joined by the Generation II branch of the family, followed by the Vortec line of motors that branched off with more changes. Over the years, interchanges between these engine generations has gotten a little more complicated.
Old ideas about what works and what doesn’t need to be updated. Computer-controlled ignitions, transmissions, and various forms of electronic fuel injection were new in the 1990s, and technology continues to advance the performance that the small-block Chevy is capable of producing.
Though a small-block hasn’t been bolted into a production-built Chevrolet in more than two decades, Chevrolet Performance continues to develop improved components for the SBC as well as crate engines. If fact, several small-block crates make more power than any production version did, even from the muscle car heyday! Plus, these engines deliver good idle quality, low maintenance, less noise, and better fuel economy! It is a delicate balancing act that is not easy to do. The company continues to improve the parts available for Gen I– and Gen II–based engines with new blocks, heads, roller cams, aluminum intakes, and other parts to continue to push the performance envelope that was first defined in 1955.
Meanwhile, those of you into older car restoration, racing, or rodding can still find everything you need to build a stock 250-hp cruiser small-block or a 1,200-hp turbo-charged motor set on kill. Between Chevrolet Performance and a healthy, enthusiast-driven aftermarket, almost anything you could want for a small-block Chevy is available; oil pan to throttle body or flexplate to water pumps, everything is available!
This book contains information on all of the small-block motors made from 1955 through 1996. It covers Gen I, Gen II, and the Vortec small-block engines introduced in 1996 so you can identify the parts you have and the parts you need to assemble a smooth-running, great-performing powerplant.
CHAPTER 1
CYLINDER BLOCKS
Block casting numbers are found on the ledge to the rear of the number-7 cylinder on the driver’s side of the small-block V-8s. The casting date of the block can usually be found on the rear of the case on the passenger’s side of the block on a ledge behind the number-8 cylinder. Some block casting dates are found at the rear on the driver’s side.
When you look at casting numbers and stamped numbers, in any part surface, sometimes the numbers are not as crisp and clear as they could be. Sometimes an 8 looks like a 3 or a 6. Also, individual digits in a number may be missing. The last digit may be missing or perhaps it just can’t be discerned by the eye. At times, Chevrolet ground off the cast number and replaced it with a number stamped by hand. These were rare instances, but they did occur.
Casting dates are usually expressed this way: “C 18 4.” In this example, the C means the month of March, 18 is the day of the month, and 4 is the last digit of the year. This last digit may mean 1964, 1974, 1984, or 1994, so you must also check the other characteristics of the block to determine in which decade and year it was made. Some parts have the decade and year cast on them; these identifiers look like this: “C 18 84.”
The block casting number “3896944” is found on a ledge at the rear of the block on the driver’s side. Sometimes you really need to check the numbers, as the last three digits are tough to make out in this example. The number on this block identifies it as a 283.
Chevrolet introduced new model years in September or October of each year, so when you see a casting date of “L 16 7” for example, this indicates a casting date used in the 1968 model year because it translates into December 16, 1967. A 1968-model Camaro assembled on January 6, 1968, might contain a number of parts that were cast in December 1967. Casting dates should precede hand-stamped engine assembly dates.
The engine assembly date and which factory assembled the engine are indicated by numbers and letters that are stamped into the block when the engine is assembled and placed into a specific vehicle at the factory. These stamped letters and numbers are usually found on a ledge forward of the number-2 cylinder on the passenger-side deck of the block. These stamped symbols are visible after the motor is assembled. The stampings show the month and day of the month the engine and vehicle assembly took place. At the end of the stamped symbols, the one-, two-, or three-letter engine suffix code identifies what type of motor it is, what type of vehicle the motor went into, what type of transmission was originally mated to the engine, and other features. Finally, on later blocks, there are also numbers that match the last five, six, or seven digits of the Vehicle Identification Number (VIN) that has been assigned to the vehicle.
The block casting date, which is the date the block was made, is found on a ledge at the rear of the block. This is not the date when the engine was assembled.
A block casting date of “L 5 6” is found at the rear of this block and translates to December 5, 1966. The “L” stands for the 12th month of the year.
The engine assembly date and the suffix code tell you about the original engine and vehicle in which the motor was placed. This information is usually found on a ledge on the front of the engine block on the passenger’s side. “VI027DE” tells you that this engine was assembled in the Flint, Michigan, plant (F); in the 10th month (October); on the 27th day. The “DE” suffix code in that year (1968, which is found with the block casting date code at the rear of the block), indicates a 307-ci small-block and manual transmission. Many later blocks also have a portion of the VIN stamped in this same location.
An example of a hand-stamped engine assembly date and suffix code looks like this: F0213ZE 023456, which translates into an engine assembled at the Flint (F), Michigan, factory on February 13 (the second month, 02, 13th day, 13)—years are not stated here—and a 327/250-hp engine (in 1965) with a manual transmission and A/C (ZE). The number also indicates that the car was a Chevy II that was the 23,456th vehicle assembled in the series.
All of these casting numbers and stamped numbers are consulted when someone wishes to determine if this is a numbers-matching engine and vehicle. Even more information is available on the trim tags, VIN plates, and hidden VINs and casting numbers, codes, and dates, which are found on other major powertrain components and vehicle frames. Whether the numbers match can be extremely important to someone who is buying a restored or restorable classic, and it can have an effect on the desirability, originality, and value of the vehicle. Knowledge of the correct casting numbers, date codes, suffix codes, and engine assembly code stampings help a buyer decide whether a 1965 Corvette with a 327/375-hp fuel-injected engine is an original numbers-matching car or not.
If the block has previously been decked (a machining operation to ensure the flatness of the block surface or to reduce the piston deck to block deck height to 0), these stamped letters and numbers may have been machined right off the passenger-side block deck surface and may no longer be visible. Engines that were replaced under factory warranty might use the CE suffix code or may not have any assembly or suffix code information at all. Also, criminals may have restamped the block in order to fake a more valuable or rare