I use a 4 lb cap on my 1950 (51 engine) 216. 1941 Radiator.

I also have an overflow system that works perfectly.

You may have overfilled the radiator. Without an overflow tank the water should be about 2 inches below the bottom of the filler neck covering the tubes when cold.

Last edited by Otto Skorzeny; 12/04/2023 12:01 AM.
1950 Chevrolet 3100 (Ol' Roy)

1939 Packard Standard Eight Coupe (The Phantom) | 1956 Cadillac Coupe de Ville (The Bismarck) | 1964 Ford Galaxie 500 coupe |1966 Ford Mustang (Little Red) | 1969 Pontiac GTO (The Dishpit) I 1979 Ford F-100 | 1976 Ford F-150 (Big Red) | 1995 Ford F-150 (Newt)