They are great trucks, I beat the hell out of one for over 6 years and its still alive and kickin as far as I know to this day. Mine was a 352 4 speed, but I put in a 390 and a car toploader 4 speed later on. I loved that truck and would jump at the chance for another to this day.
You can swap disc brakes from a late 70's full size van right onto them, same king pins and stuff on the I beams.
They are classy and fun to drive, heres a pic of my old beast:
The prices on these are going up all the time, 1500 is a deal, check under the hood for rust, the core supports go on them, and the tops of the inner fenders where the fenders bolt on.
Cool old trucks, good luck!