The Edelbrock Performer RPM Air-Gap Intake Manifold incorporates race-winning technology. The air-gap design features an open air space that separates the runners from the hot engine oil resulting in a cooler, denser charge for more power. It includes standard oil fill and PCV, as well as early air conditioning support bracket accessory bosses. It has no provision for exhaust heated chokes and no exhaust crossover. The aftermarket 4-bbl carburetors are not compatible with Auto Overdrive Transmission (AOD).