Hotrodit, sorry haven't posted before, just saw your topic. My driver is a 66 C20, Mine has 283, also with granny low 4 speed. A C20 is a 3/4 ton but most 1/2 ton parts will interchange. You should have 8 lug wheels, 1/2 ton had 6. My truck has 113,000 HARD miles, Its used here on the farm to hall hay, manure, whatever and pulls a car trailor and hauls parts to flea mkts. Friends say they feel sorry for it, but I think it is happy doing what it was designed for. Has a little rust in bottom of doors and lower rear quarter of front fenders that I should fix someday. Best thing, they are dependable. LMC has good list of parts, they're not cheap but good co. to deal with. Luck with the new ride and if I can be of any help let me know.