Mr. Gasket Large Port Small Block Chevy Intake Gaskets form an airtight, leak-proof seal and can be trimmed into an infinite number of configurations to modify the intake ports to your exact specifications. Engineered specifically for small-block Chevys with 2.310-inch by 1.310-inch intake ports and made of a cellulose/nitrile composite, theyre .125-inch thick and precision die-cut for exact fitment and years of trouble-free service. Mr. Gasket Intake Gaskets ensure optimum torque retention, ideal crush resistance, and excellent sheer strength, sealing with minimal clamp force yet still releasing easily every time. An upgrade from Original Equipment gaskets, theyre ideal for both high-performance and racing use and come complete with manifold end-rail seals and a distributor gasket.