Chevy engine block numbers are assigned according to the location and date of manufacture and the engine information. The five-digit prefix identifies the date and location of manufacture. This is followed by a two or three letter suffix that represents engine data such as size, model year and engine horsepower.
The engine block number is located on the engine block, though the exact location depends on the engine size. Smaller engine blocks feature the number near the cylinder head on the passenger side. In many cases, the alternator obscures the number. For large engines, the number is placed on the block above the timing chain cover. Six cylinder blocks have the number on the block near the distributor on the passenger side.