It is the size of the tubes/rows that provide the best cooling. Usually at a premium price. FOR BIG BLOCK 396/454. STAMPED AND RIBBED TANKS LIKE ORIGINAL FOR A RADIATOR THAT LOOK LIKE IT BELONGS TO YOUR CAR.
1965 1966 1967 Chevelle AC Blower Motor Resistor Mailbu SS El Camino
1965 1966 1967 Chevelle Gas tank OE Finish, 3/8" sending unit & Strap kit
1964 1965 1966 1967 Chevelle 100% Aluminum Radiator Cross Flow
1964 1965 1966 1967 Chevelle GTO Body Mount/Trunk Floor Brace Pair Right & Left
1964-1966 Chevrolet Chevelle Malibu El Camino Rear Axle Brake Lines Kit, Steel
Gas Tank Filler Neck Rubber Hose For 1964-1967 Chevelle Malibu