This Flowmaster manifold downpipe kit is specifically for 1965-1974 Chevelle/El Camino, 1967-1972 Camaro, 1968-1969 Nova, 1968-1970 Caprice/Impala/Bel Air and 1970-1974 Monte Carlo all with BBC engines. They are designed for the person who wants to use a Headers-back exhaust system while retaining the factory exhaust manifolds instead of headers. Manufactured from 2.50-inch mandrel bent 409S stainless steel tubing and high quality flanges for a leak free fit and an easy installation. Fits factory Chevrolet BBC 3-bolt manifolds. Includes donut gasket and donut sleeves.