The Edelbrock Performer RPM Vortec Intake Manifold is a single four-barrel intake which is designed for the street rod, marine and engine swap market engines and later Vortec cast iron or the Edelbrock E-Tec aluminum heads. An external water bypass boss is machined into the front of the water crossover for use on 1996 and later Vortec production engines. This broad power band makes Performer RPM ideal for street or strip. The manifold accepts square-bore carburetor only. They are intended for high-performance street and marine engines operating from idle-5, 500 RPM. The Performer RPM manifolds match Performer RPM camshaft and cylinder heads for outstanding performance.