Edelbrock part #7561 RPM Air-Gap 2-O intake manifold is compatible with street 396-502 c.i.d. Chevy V8's with large oval-port cylinder heads (1975 and earlier) or Edelbrock Performer/Performer RPM heads. This RPM Air-Gap incorporates the same race-winning technology that's been used on our Victor Series competition intakes for decades. 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. Includes rear water outlets, two distributor clamp locations and nitrous bosses. Accepts all late model alternator and A/C brackets for the street. For square bore carburetors only. Will not fit under stock hood of Corvette, 1964-67 Chevelle or 1967-81 Camaro. No provision for exhaust heated chokes and no exhaust crossover.