General Motors engine and cylinder head casting number lists are available from CastingNumbers.info, GearHeadGeek.com, 73-87.com, and OutInTheShop.com. GearHeadGeek.com and OutInTheShop.com list GM engine casting codes in numerical order and include years of production, a brief description or unique characteristics, and factory horsepower specifications for each engine.
The 73-87 website provides an index for General Motors large- and small-block engines as well as cylinder head casting numbers. CastingNumbers.info lists GM cylinder casting numbers in numerical order with the corresponding engine block, as well as details about the size, performance and associated parts for that cylinder head and engine combination. General Motors casting numbers are stamped into both General Motors passenger vehicles and trucks.