Can only speak for Oldsmobiles, but from 67 on back, the vehicle VIN was not stamped on the engine. The engine had its own serial number.
The value of the P.O.P. was that both of those numbers were in there and was the only way to verify original engines. My 66 442 has that.
I really like having my own name as the one on the P.O.P. for my Ramrod.
