To answer some of those questions, you can do a few quick things. Try looking up the rotors for a 71 and a 73 truck. If its the same part number from an on-line supplier - then they'll work. You could also try the same thing on ball joings. See if the 63 truck and the 73 truck use the same part. If not, then try going to a parts story that has both and see what the differences are. Autozone.com or another might have pictures of the things on line. That will at least get you started.
I don't think its a question of dead horse, its that people are probably reluctant to give you opinions that could be wrong.
