Description 12a RX-7 FB Exhaust Manifold gasket, This gasket goes between the exhaust manifold and the engine block. Only 1 is required for each engine. This gasket will fit 12a engines only. Gasket is compatible with the following series Rx-7 FB 1982-1983 Mazda RX-7 FB (Series 2) 1984-1985 Mazda Rx-7 FB (Series 3) What series FB do I have? The series 1 and 2 has a smaller (shorter) radiator with an oil cooler fitted below, The series 3 was fitted with a larger (taller) radiator filling the entire radiator shroud and was fitted with a small passive oil cooler that looks like a tiny beehive below the oil filter itself.
