There is a book (I've seen it) that tells what parts off of like the 60s and 70s Fords will fit on a 56 Ford pickup. Like what gas tanks will interchange, what steering columns will interchange, disc brakes setups, etc.

 

The Hollander Co used to supply salvage yards/used parts dealer with their parts interchange manuals. Not everyone could learn to use them but those who could found then very handy. I haven't seen one in years. They were a very large yellow(ish) book with hundreds if not thousands of pages, and if still available are probably electronic only now.