What you posted was the application code for the engine, meaning what the engine came out of.
If its a chevy V8 motor, the block casting number will be on the rear driver's side of the block. Look behind the driver's cylinder head, at the bellhousing flange. It may be difficult to see it, so clean the area and get a good light. An example number is 3914638. Yours should have a similar string of numbers. Near that number should be the block casting date code. Get it too, to date the block.
What does the engine look like? The older chevy V8s (283-327) had a oil filler tube at the front of the intake manifold, points distributor, ram's horn exhaust manifolds, and 4 bolt valve covers.
Post the numbers here and we'll figure it out.
Chip
