72 chevy
2S137253
11/71
71 chevy
1Z629816
02/71 - On or after 2/10 based on other entries in post #1. Has rear axle code of 02/05 and I think the engine code is a date of 02/11, but not certain.
71 gmc
S132212
6/71
70 chevy
0A153628
06/70
72 chevy
2S140714
12/2/71 < build date < 01/25/72. Another confusing POP. Build month of L? Rear axle Y2S30? I think 336 represents Dec 2 for the transmission build date.