XX Carbon Gaskets made of Percy's proprietary 100% carbon material. These gaskets can withstand long term direct exposure to over 2000° fahrenheit. They offer superior sealing ability on the worst flange surfaces and are perfect for nitrous, turbo, and blower motors. XX Carbon Gaskets are available for every popular application and can also be custom cut or easily port matched.Pit Stop USA offers Percy's XX Carbon Header Gaskets - SB Ford 221-302 Oval, Round 1.5" x 1.125" 68018 at low everyday prices. Be sure to check out all of our products from Percy's High Performance including Percy's High Performance Small Block Ford Header Gaskets.