Bill knows Pontiacs. So do I. We've both told the OP the same thing. The partial VIN on the block is meaningless regarding ID of the ENGINE.
To correctly identify a Pontiac you need: Engine code (2 digits, alpha-numeric, stamped on the front of the block NEAR the partial VIN); date code (by the distributor) and block casting number (on bellhousing flange), both CAST "in". That's IT.
Relax. It isnt that complicated... (:-