Jerry,
This was, literally, the manual to assemble the truck. The drawings were created by the engineers as they made design changes to the truck. As the model years progressed, they would only do new engineering drawings if something changed -- a lot like the service manuals: You get the '60 manual, and you get manual updates for '61, 62, and so on.
Since it wasn't really designed for us, I've taken to marking pages with call-out tabs and keeping notes in the back of the book.
Brian
