Frame rail options

The A-body frame rails aren't all that hard to find. Probably why AMD doesn't make them. The only big that that changed from 67 up to 76 is the mounts for the bumper. 67-73 have two bolts for the standard bumper brackets, 75/76 have a single bolt for the shock mount bumper bracket, and '74 was a transition. Early '74's had one bolt for the shock bumpers, mid-'74 on had all three mounting locations so they'll work on anything. The mounting locations are captured nuts inside the frame rails. You can use rails with the "wrong" mount, but you'd have to work out a way to mount the front bumper. If you can weld it's not that big of a deal, and if you're swapping frame rails you can weld, so, it's not a huge deal. Just easier to have rails with the right mounts.