Designed for Mark IV big block Chevrolet engines equipped with Rectangle Port cylinder heads, these intake gaskets use a cellulose/nitrile composite material that maintains seal integrity under heat, pressure, and repeated torque cycles. The set includes molded manifold end seals and a distributor gasket to complete the installation. Suitable for OE replacement as well as high-performance street builds, drag racing, and oval-track applications. Note: This version is manufactured without silicone beading.