Your 63 C-20 is a heavy duty truck with a heavy duty frame, front suspension, engine, transmission, and a 4.57:1 HD rear end. You just don't change all this stuff without serious work and associated cost. Even if you can find a donor C-10 to provide the parts most of them will need to be rebuilt anyway. After all the replacements are 50+ years old also. Find a 4.10 rear end, there are numerous posts about this issue. I believe there are 8 lug disc brake conversions available now. Check with ABS in Orange. There are aftermarket suppliers that can provide 8 lug wheels. Wheelsmith is in Corona. I'm sure there are others locally.
Otherwise sell it and find a C-10 you love and spend the cash on it.
Fred
