Gasket Kit, Valve Cover BBC Big Victor Heads Fabricated from performance CRC (core-reinforced-composite), Edelbrock valve cover gaskets provide excellent sealing integrity and conformability for easy installation. The multi-layer construction has two highly compressible, high rubber content, fiber-reinforced outside layers which are chemically bonded to a high strength composite core. This unique core-reinforced construction has a radial strength to resist high-vacuum or blow-out conditions