1975 Pontiac Grand Am 5.7L V8 GAS;. 1975 Pontiac Grand Am 6.6L V8 GAS;. 1975 Pontiac Grand Am 7.5L V8 GAS;. Gates - Driven By Possibility. Fuel Tank Cap;. Pre-Release Fuel Tank Cap;. Excess fuel system pressure is relieved through an internal spring and gasket valve that is specially designed to allow venting without losing liquid fuel.