John, unless you know the tonnage of the "Ford" orifice as opposed to the "GM" I would recomend using the factory orifice .. any more flow or any less flow could cause problems. Too much refrigerant feeding into your evaporator may make it back to your compressor as liquid and won't compress :-(. Too little and your head pressure could be to high with too low of a suction and wear your compressor out prematurely . I have dealt with a "heat soaked" condenser all summer her in central FL. New radiator/stock fan/original condenser.. will be trying dual fans by next season... hope I haven't been captain obvious on your post... Joe. Oh ya,I am running R12 in my T