[83_shortwide]

I have the book GM LS-Series Engines: The Complete Swap Manual written by Joseph Potak. I dont know if it is any good, I have nothing to compare it too.

This book says "All oem engines are stamped with the last few digits of the VIN of the vehicle that the engine was installed in at the factory. Sometimes these numbers are useful if other identifying marks prove unreliable in engine identification.''

Looks like the numbers are on the drivers side, back corner of the block next to the flywheel.