Small Block Chevy casting numbers are engine serial numbers cast on the engine block, cylinder heads, intake and exhaust manifolds. They are used to identify the series of engine castings designed for a specific model of car. You can use Chevy small block casting numbers to ensure part accuracy in your classic car restoration, or if you’re shopping for a car, to make sure you’re getting what you’re paying for.
I would use an engine casting number decoder book in some scenarios. Imagine this…
- You’re looking at a 66 Chevelle someone has for sale and you want to know if it has the right engine.
- Or… you’re at a swap meet and a guy has some engine parts that he’s selling. There’s a couple of camel hump heads that he says are on a 327 that “came out of a Corvette.”
- You’re spending the day at a “U-Pick” junkyard. You’re looking for an engine core for your classic car restoration project and come across a 65 Impala SS with an engine.
To be sure, you would need to look up the casting numbers.
The Chevy small block engine casting number can be found on the bell section of the block, just behind the passenger side cylinder head. This number will indicate some notable design specs such as 2 or 4 bolt main bearing caps, what model cars it was installed on, the years it was installed on those cars, and in some cases, the horsepower rating. Some casting numbers were used for a number of different models so if in doubt you will need to look for the suffix code stamped on the engine.
The Chevy small block release date would help you narrow down the decade the block was released if the use of the release number spanned decades, such as the late 60’s to early 70’s.
Suffix codes were numbers stamped into the engine block at the time of assembly. They can tell you what car the engine was originally installed in, the year, and even the number of options for the car.
In general, when shopping for casting number decoders, you will find casting numbers and suffix codes in separate books. Casting number information for intake and exhaust manifolds, or cylinder heads, is usually included in engine block casting number decoder books. Be sure to look up the years of coverage when selecting a cable box. Some casting number decoders only cover classic years from the 50’s through 80’s and may not provide information on late model engines.
Some of the most useful decoders come in smaller sizes that fit in a coat pocket or toolbox, which comes in handy for junkyard scavenger hunts or swap meets. Others come in larger standard book sizes and will generally include more images and diagrams than the smaller text sizes.
In any case, small or large, you will find them indispensable and well worth the price. Most release number guides range in price from $15-30 US.