I have a 1949 F1 ford pickup. I have put in a new Aluminum US Radiator. I am running the 8BA flathead. Should I use a 4 lb. cap or move up to a 7 to 10 lb. cap?
if you have it use the 4#, alto the radiator will handle higher pressures the rest of the cooling system was not designed for higher pressures, you can use a 7# but i would not go over that