What parts are you swapping? Engine? Tranny? Body?
I've been using online parts suppliers to "research" swapable parts for my Astro van project.
1) Look up the part you want to swap, get a part number then
2) look up the car you want to swap "from" and check the part numbers...
Did you guys know the Astro Vans use nearly the identical front suspension as the '77-'96 "B" body Caprices, Parisiennes, Olds,Cadillacs and Buicks? Front spindles, rotors, calipers, bushings, bearings, ball studs..... All the same.