1955-1956 ENGINE CODE IDENTIFICATION

   The 1955 and 1956 Corvette engine code stampings were identical in terms of design. The stamping, which was stamped on the block prior to the installation of the cylinder head, consisted of 11 or 12 alphanumeric characters that were stamped into the horizontal block pad. This stamp pad was located immediately forward of the right side cylinder head on V-8 engines. The V-8 pad is 3-1/8" long and is considered the "short pad." This pad was used up until january of 1965, when it changed to a length of 3-9/16" - 3-5/8" long.

    The first seven numbers represent the engine unit number that was produced in that engine plant. A gang stamp stamped the first five of these numbers. The next two numbers were stamped individually into the block so that the gang stamp holder would only necessitate a new number change every 100 engines. The final four or five characters were also stamped into the block in a gang stamp holder. All engines, including six cylinders, were numbered as they were produced at the engine assembly plant. All engine unit numbers started with 0001001 and increased numerically as engines were produced. All 6- and 8-cylinder engines were numbered separately.

    Only two engine plants were producing engines at that time. They were the Flint, Michigan, and the Tonawanda, New York, plants. All Corvettes that were equipped with small blocks used only Flint built engines. No Corvette will have a Tonawanda engine in this time period. After the engine unit number, a letter "F" or "T" will appear to designate either the Flint, Michigan (F) or Tonawanda, New York (T) plant. The next two numbers will represent the model year of that engine. In this case, it will either be 55 (1955) or 56 (1956). The last letter or letters will represent the specific engine suffix code that was assigned that assembly. This code usually specifies the transmission option or other pertinent information vital to that engine application.

So it may look something like this: 00001301 T 55  (and 1 or 2 Letters). Which in this example the code would decipher as the 301st engine, Tonawanda Plant, 1955, and the letter references say the tranny to mate to this particular engine.