Engine and Performance Recommendations for this cylinder head: Serious street performance, Oval Track, and Bracket Racing 7000 rpm, 383/400 c. i. The result of three decades of cylinder head development, Iron Eagle heads incorporate features that were previously available only in expensive aluminum cylinder heads. We designed Iron Eagle heads for street performance, bracket racing, oval track competition, and high-performance marine use. We offer five different intake ports165cc, 180cc, 200cc, 215cc, and 230cc that cover virtually every engine application. Dart Iron Eagle heads have standard features you don't get in other factory and aftermarket cast-iron cylinder heads. Long-wearing bronze valve guides (except S/S), multi-angle intake valve seats, and hardened and radiused exhaust seats are standardPit Stop USA offers Dart Iron Eagle Platinum Cylinder Head - Bare - 64cc Chamber - 215cc Intake Runner - SB Chevy 327, 350, 400 - Angle Plug - 2.05", 1.60" Valves 10510020P at low everyday prices. Be sure to check out all of our products from Dart Machinery including Dart Cast Iron Cylinder Heads - Small Block Chevy.