I found a guy around here where I live that has a 4 car garage filled to the max with Parts catalogs, service manuals, dealer packets, repair manuals, maintance folders, andthing and everything you can even think of. I bet there were 100,000 books/folders whatever in his garage. He has everything that is American made, all listed from year to year, to model. I saw items from 1939's 1940's. There are alot of items that he doesn't get, but by chance he might have it next month.
I got a GMC Master parts catalog with pic from 70-71
I got a 1946-72 GM Truck Master parts catalog w/ pic
and I got a 1972 GMC Truck wire diagram catalog
I was pretty happy, only wish I could have stayed longer