Edelbrock part #75854 RPM Air-Gap Dual-Quad 351W intake manifold is designed for 351W small-block Ford V8 applications. This intake offers performance improvements in the 1500-6500 rpm range. The large runners feature our unique Air-Gap design that separates the runners from the hot engine valley for a cooler, denser charge and more horsepower. Includes bosses for rear water crossover. Carb center to carb center is 6-7/16". This manifold offers our long lasting bright chrome like EnduraShine finish that matches chrome and polished accessories.