47 chev,
I understand that the recommended pressure caps for '54 and later 235 engines were 4 psi in a truck engine and 7 psi in a car engine. I think that earlier truck engines (216 and 235) both had 0 (zero) pressure radiator caps.
Maybe someone else knows if pressures greater than 0 psi were safe with other '47 parts (specifically, radiator and water pump).
Someone will correct me on this, if I'm wrong.
Tim
