I'll tackle a couple of the major things.
60-61 have the 'eyebrow' hood.
60-62 have torsion bar front suspension.
63 is last year for the 'dogleg' windshield
63 up has basically the same frame as 67-72.
Leafsprings were optional, either Gmc or Chevy could get either option.
I admit I have a hard time with 64-66......identified by emblem placement, which I dont know
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