There is more to a 1-ton than the rear end. A major ones are springs and brakes. There are a lot of folks that "geared-up" to find out the truck handles poorly at higher speeds. The suspension and steering were not designed for much above 50 (my 1951 47 mph in the specs). Not trying to talk you out of it, might just think about buying a 1-ton wrecked donor and swapping a lot of parts if you are thinking loading it heavy and driving fast.
