Edelbrock Part # 7551 Performer RPM Air-Gap Oldsmobile 455 intake manifold is intended for aggressive street/ strip big-block Oldsmobile applications. Designed to optimize horsepower production from 1500 to 6500 rpm, this manifold will perform best with engines that have an aggressive camshaft profile that will take advantage of the increased flow this manifold can provide. This intake manifold features our popular Air-Gap design that separates the runners from the hot engine oil, resulting in a cooler, denser air charge for more power. This manifold is compatible with stock heads, but has been designed to work with our RPM cylinder heads #60519 for optimal performance. Not compatible with EGR or spread-bore carburetors.