Edelbrock part #75163 RPM Air-Gap intake manifold is designed for 262-400 c.i.d. Chevy V8's with 1996 and later Vortec (L31) cast iron or Edelbrock E-Tec aluminum heads. This intake manifold is based on the powerful Performer RPM Vortec #7116. 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. An external water bypass boss is machined into the front of the water crossover for use on 1996 and later Vortec production engines. Includes rear water outlets nitrous bosses a temp sensor boss that clears all waternecks two distributor clamp locations and a heater outlet boss that's angled for proper fit over the valve cover. Accepts 1976 and later alternator and air-conditioning brackets for street installations. For square-bore carbs. No provision for exhaust-heated chokes and no exhaust crossover. Will not fit under stock Corvette hood. This manifold offers a durable black power coated finish for long lasting protection and a distinctive look.