There is a machined pad on the engine block ahead of the passenger's side cylinder head. A stamped (not cast) number there is supposed to identify the original application of the engine, usually with a 2 or 3 letter code following the numbers. If the top of the block has been machined during a rebuild. those numbers could be missing. Then you will need to rely on the casting number behind the driver's side head to get a basic idea of the engine size and a general range of applications. It's not uncommon for a casting number to spam several years of production, and vehicle applications, however.
Jerry
