The Edelbrock Performer RPM 302 Intake Manifolds are dual-plane, high-rise intakes with 180 degree firing order to produce incredible top-end horsepower while retaining good throttle response. Their larger plenums and runners match the free-flowing exhaust, high-lift cams and other modifications of a high output engine. The intake manifold directs the air or air-fuel mixture from the throttle body to the intake ports in the cylinder head. The flow typically proceeds from the throttle body into a chamber called the plenum, which in turn feeds individual tubes, called runners, leading to each intake port. They are intended for high-performance street engines that run up to 6, 500 RPM. They are not for emissions equipped engines.