I use Shell Rotella 15W-40 Diesel oil for the added zinc content.
Re non-detergent oil; I have a friend with a 1934 Duesenberg that can only use non-detergent oil. That's because the engine has never been rebuilt. Using a detergent oil would risk loosening 90 years of sludge inside the engine with potentially catastrophic results.
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)
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