If your tank is still filling the fuel filter with rust, you should look at one of the fuel tank coatings sold by Eastwood and others.

I used a sloshing compound on my '56 Cadillac 20 years ago and it hasn't deteriorated at all.

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)