The Edelbrock Performer RPM Intake Manifold is intended for high-performance street or competition engines that run up to 6, 500 RPM with maximum power. The front height of the manifold measures 4. 20 and the rear 5. 25. The Performer RPMs are dual-plane, high-rise intakes with a 180 degree firing order. This manifold produces incredible top-end horsepower while retaining good throttle response. 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. It is not for emissions-equipped engines. A Performer RPM intake gives you the ultimate in street high-performance. It provides power like a single-plane and throttle response like a dual-plane.