$476 to assemble an 8 3/4 diff

This is exactly why no one wants to work on old stuff for money. Unless you figure you're time at $25/hr they think they're getting screwed but the same rear end work on a newer Ram would be couple grand with basically same **** (Bearings, Ring & Pinion, Axles, Seals, Etc)
Yeah thing is, most think old cars are "easy" for some reason. I always say "mechanics bitched and complained in 1972 also..." :)

put it this way , right now would you want to do a water pump on an LA small block? easy right? done it many times but do you want to do it right now? Thats the life of a line mechanic. You have to do 5 a day to make good money LOL!