SCE's legendary Pro Copper Cylinder Head Gaskets, recommended by the best professional teams to seal 7,000 horsepower Top Fuel motors, are equally potent in 500 horsepower street and strip motors. They're made from C11000 ASTM B-152-92 copper sheets, annealed to Rockwell F-32, and then skin sealed in engine sets. SCE introduced the first embossed copper exhaust gaskets in 1995, and they are still the best way to seal warped or uneven exhaust manifold and header surfaces. These gaskets require sealant and O-rings in block or head.