The Edelbrock Performer RPM Intake Manifolds have a high-rise, dual-plane layout, with patented runner tuning and a 180 degree firing order. The Performer RPMs have larger plenums and runners to match the free-flowing exhaust, high-lift cams, and other modifications of a high-output engine. They produce incredible top-end horsepower. They do not compress well when used with an aluminum intake manifold. The factory composition-type embossed gasket also works satisfactorily. They are intended for high-performance street or competition engines that run from 1, 500 to 6, 500 RPM. The port flange has extra material above the runner for use with cast iron 455 heads. This manifold has provisions to add oil fill tube but no provisions for exhaust heated or stock-style choke.