Cometic GM Gen II/ Mark IV BB 4.630in Bore .040in MLS (396 / 402 / 427 / 454) Head Gasket

This Cometic Multi-Layer Steel (MLS) head gasket is built with embossed outer layers coated in Viton, a heat-resistant rubber material rated up to 482°F. This design is crucial for sealing high-output engines, especially those combining aluminum heads with cast iron blocks, as it can handle the shearing forces that arise from the different expansion rates of these metals. The gasket's compressed operating thickness is precisely 0.040 inches, and its multi-layer stainless steel construction offers increased strength and resistance to corrosion, while also allowing it to rebound effectively.

Because it's made from multiple layers of stainless steel, this gasket provides robust sealing performance without the need for additional sealants. The center shim layer is also stainless steel and can be varied to meet different thickness requirements, making these gaskets adaptable for a wide range of applications. This particular gasket is designed for a 4.630-inch bore and fits many Chevrolet Big Block V8 engines, including those found in models like the 1965-1975 Chevrolet Impala, 1967-1972 Chevrolet Camaro, and 1965-1974 Chevrolet Corvette.