Designed for up to 8500 RPM. Single-plane design. For standard flange throttle bodies. Runners have plenty of material for port matching. Machined rear breather boss is included. Accepts 4500 series carburetor. Can use 1 or 2 spacers to tune performance. Includes nitrous bosses on runners. Product Features:For 4000 to 8000 RPM High-Performance EnginesAll-New Runner Design for Maximum PowerSingle-Plane High-Rise IntakeLow Profile Works Well w/Limited Hood ClearanceFor High-Performance Street to Drag/Circle RacingAccepts Square Bore CarburetorCan Use 1 Or 2 in. Spacers To Tune PerformanceIncludes Nitrous Bosses on Runners