These new Performer RPM intake manifolds are designed to fit 1958-1965 Chevrolet 348/409 "W-Series" big-block engines. Two version are available; one for small-port cast iron heads and the other for factory large port or with our Performer RPM "W-Series" heads #60809 or #60819. They both deliver improved performance in the mid to high rpm range when combined with Edelbrock carburetor's. Both also feature a front mounted oil fill tube for those who want the nostalgic look of our Classic series valve covers with no breathers. Includes Oil fill Tube (not installed) and matching push-in breather cap. The Oil Fill Tube and Breather are also sold separately as #4803. For square-bore carburetor's only. Edelbrock Performer RPM Intake Manifold 7158 Cast - Non-EGR - 1500-6500rpm - 58-65 Chevy W BB 348/409 - For Sq. Bore - Includes Oil Fill Tube/Push-in Breather/Pcv Baffle - For Sm. PortDesigned for 1500 to 6500 Performance1958-1965 W Series 348/409 Big Block EnginesFor Large Port Or RPM W Series HeadsPit Stop USAoffers Edelbrock Performer RPM Intake Manifold 7158 at low everyday prices. Be sure to check out all of the products from Edelbrock including Edelbrock Engine Parts and Accessories, Edelbrock Intake Manifolds, Edelbrock Intake Manifolds - BB Chevy, Edelbrock Intake Manifolds - BBC.