[thekid54]

60-66 frames are not the same. 60-62 are the same, and 63-66 are the same. I've heard 67-72 frames are the same as 63-66, except for the front fame horns where the front bumper mounts.

Here are some differences I can think of off the top of my head. I'm sure others will think of more:

60-62: partially boxed frame with large X-member, torsion bar front suspension, front cab mounts are different than 63-66, frame rails are farther apart in front and back (bumpers & bed sub-rails will not interchange without modification), grille surround is also different (cut outs on the bottom for the frame rails)

63-66: no boxing & no X-member, coil front suspension, front cab mounts are different than 60-62, bumpers & bed sub-rails from 60-62 will not interchange without modification