We just swapped a 73-93 Dodge pickup frame under the 70 Sweptline sheet metal the last time we did one. If its a short box, everything pretty much bolted together. I think we had to trim the top 1" off the frame hump over the rear axle and replace it with a flat 1/8" x 2" bar stock. I really think every thing else just bolted into place, but its been 15 years ago.
6 months later when we swapped the small block for a big block without any factory parts, we ran into a few challenges, but the cab to frame was pretty straight forward. Gene