Maybe the guy that owned the trucks lived in the Midwest rust belt? A rust free 73-80 would bring that kind of money, or at least a lot of people are asking that kind of money here, but it has to be free of rust. Drive train doesn't seem to matter much, unless its a factory 440. The roof and the radiator support are the worst areas, after the floors and wheel wells.
Any pre 94 trucks are getting stupid, price wise, and its pretty hard to find one that still has good sheet metal. Gene