Just bought a 1965 c-60 for the same reason. Check out the thread I had already posted:
http://67-72chevytrucks.com/vboard/s...d.php?t=321822
The cab is the same from what I've seen so far. The firewall did look a little different. On those big trucks the engine sits a lot further down in the engine bay than on the c-10's. The hood, doors and heater are the same. The front fenders, inner fenders, grill surround, core support, front bumper are all different.