RPM Air Gap Intake Manifolds Edelbrock engineers designed the first and only dual-plane ... manifold with the powerful air-gap design the same ... horsepower from 1500 to 6500 rpm with 9.5:1 compression. 7501 SB Chevy ... 205.99 7561 BB Chevy (oval-port ... 235.99 7562 BB Chevy (rectangular-port ... 329.99 7516 SB Chevy Vortec 1996 and later . . . . . . . . . .$225. ... 99 7531 AMC 304-401 c.i.d engines for 1970 later .$272.99 7530 AMC 290- ... 390 c.i.d. engines for 1967-69 . . . .$272.99 Some High ... that can give you top end power without affecting the midrange. What Edelbrock ... 2,500-6,500 RPM range. 5001 Small Block Chevy ... The Victor manifolds boost power where engines use it the most 3,500-8,000 RPM range. ... square-bore Holley carbs. Small Block Chevy (not for use w/1987-up cylinder heads) ...