In any engine, use the lowest octane rated gasoline that your engine will operate on without knocking, pinging, dieseling, or running-on. There is absolutely ZERO benefit to using premium fuel in an engine that doesn't require it (despite what the advertising would have you believe).

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)