Chevy Small Block Casting Numbers – What Are They, And How Do I Use Them?

Small block Chevy casting numbers are engine series numbers cast into 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 the accuracy of parts on your classic car restoration, or if you are car hunting, to ensure you are getting what you are paying for.

You would use an engine casting number decoder book in a few scenarios. Picture this …

  • You are looking at a 66 Chevelle that someone has for sale and want to know if it has the correct engine.
  • Or … you are at a swap meet and a guy has a few engine parts he's selling. There is a set of camel hump heads he says are off a 327 that "came out of a Corvette."
  • You are spending the day at a "U-Pick" junk yard. You are looking for an engine core for your classic car restoration project and you run across a 65 Impala SS with an engine in it.

To know for sure you would need to lookup the casting numbers.

The Chevy small block engine casting number can be found on the bell housing 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 models of cars it was installed in, the years it was installed in those cars, and in some cases the horse power rating. Some casting numbers were used for several different models so when in doubt you will need to lookup the suffix code stamped into the engine.

The Chevy small block casting date would help you narrow down which the block was cast if use of the casting number spanned decades, such as the late 60's through the early 70's.

The suffix codes were numbers stamped into the engine block at assembly time. They can tell you which car the engine was originally installed in, the year, and even the option series 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 generally included in the engine block casting number decoder books. Be sure to look for the years of coverage when selecting a decoder. Some casting number decoders only cover the classic years from the 50's through the 80's and may not provide information on late model engines.

Some of the most useful decoders come in smaller sizes that will fit in a coat pocket or tool box, which comes in handy for junk yard scavenger hunts or swap meets. Others come in larger standard book sizes and will generally include more pictures and diagrams than the smaller text only sizes.

In either case, small or large, you will find them adequate and well worth the price. Most casting number guides range in price from $ 15-30 US.

Source by Carl M King