Product details:

These S/B Chevy tight-fit headers fit even difficult applications where space is limited. For round port S/B Chevy. 1-1/2 inch primary with 2-1/2 inch collector. These block hugger headers are ceramic coated headers. Complete with reducers, gaskets, and bolts. These shorty headers are designed to make difficult installations easy. - Drivers side collector isapprox. 2 inch from pan rail - Passenger side collector isapprox. 1/2 inch from pan rail - Flange thickness isapprox. 0.212 inch - Will NOT fit angled plug heads. This header will NOT clear the 'clam shell' style engine mount commonly used as the stock type engine mounts on 1973-up Chevy applications. - Header Dimensions(GIF)Item Details - Header Dimension Explanation Chart