Designed for 1970-91 304-401 c. i. d. and 1967-69 290-390 c. i. d. V8's, RPM Air-Gaps incorporate the same race-winning technology as our Victor Series competition intakes. The air-gap design features an open air space that separates the runners from the hot engine oil for a cooler, denser charge and more power. For square-bore carbs. Includes standard oil fill and PCV provisions as well as early air conditioning support bracket accessory bosses. No provision for exhaust-heated chokes. No exhaust crossover. ** Carburetor Recommendations: Edelbrock Thunder Series AVS or Performer Series carb, 600-800 cfm Installation Notes: Recommended intake gasket: #7213 or Fel-Pro MS96011. #7531 must use factory style metal valley tray. #7531 has two center bolt holes offset. Manifold height: A-4. 45", B-5. 77"; Carb pad height: 5. 11" . Port exit dimensions: 1. 04" x 2. 10". Bracket #8034 required for 1979 and later vehicles. Camshaft Recommendations: Performer RPM #7132.