The Edelbrock Performer RPM 2-O Intake Manifold offers the latest technology in dual-plane high rise design and builds outstanding horsepower while maintaining good torque and drivability. The Performer RPM's are dual-plane, high-rise intakes with a 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. They are intended for high-performance street engines that run up to 6, 500 RPM. They are not for emissions equipped engines.