The Edelbrock Performer RPM FE Intake Manifold has a provision for adding the PCV (Positive Crankcase Ventilation) or breather flange at the rear, and no exhaust crossover passage. The modular design of this manifold incorporates the latest air flow technology for maximum torque gains in the mid-range. Their dual-plane constant cross-sectional area design builds low and mid-range acceleration, while optimized runner paths make top-end horsepower. Base manifold is CNC port matched to upper manifold for maximum power and accepts all stock hardware. The upper is powder-coated light titanium gray, base is as-cast. They are intended for high-performance street or competition engines that run from 1, 500 to 6, 500 RPM.