You are probably not going to get many responses for swaps on trucks that big but you DON'T NEED any. Since you have both the 57 and 95 a tape measure will give most of the info needed. The engine should be a 305 or 350 and the auto trans a 4L80E. The NV4500 is a straight bolt up (remember a pilot bushing) but my NV uses a hydraulic throw out slave cylinder. I used the dual master cylinder from a 60-62 Chevy pickup to give both brake and clutch action. The short answer about interchangeability is to just plan on fabricating everything from cross members to clutch linkage. Anyone with that big a stable of vehicles needs MANY tools and the ability to use them.

Evan