["QUICK-SILVER"]

Originally Posted by 'ol Pinion head

2= Pontiac division
1 = 1971 model year
P= Pontiac home plant. built B bodies & A-bodies
3004555 is the last 6 digits of the cars VIN

IF the last 6 digits had started with a 1 or a 2, the engine would have come out of a '71 Pontiac A-body built at Pontiac home plant.
As the last 6 digits began with a 3xxxxx, the '71 YC coded block came out of a B series (big car).
The two letter code YC engine was used for near 10 model years straight, 389, 400's, 455's, 350's... ALL of them basic D-port engines with standard log exhaust manifolds.

Clay