In this video I retrofit my 1975 Chevy C10 to convert from R12 to R134a AC refrigerant. The steps involve flushing all the old oil out of the system, installing new o-rings, new drier and orifice tube, adding oil and R134a refrigerant.
Search for an ac receiver drier kit for your c10. You’ll want a drier, an orifice tube and orings. That is standard stuff for any time you do ac work to your vehicle. The conversion kit you can find on Amazon for cheap, just search for r134a conversion kit. And then of course you’ll need to flush the ac lines and then add some sort of r134a compatible oil
