Cometic Chevrolet Mark-IV - GM Gen-V/VI Big Block V8 .066in MLS Cylinder Head Gasket - 4.310in Bore

Starting with a compressed thickness of 0.066 inches, this Cometic Multi-Layer Steel (MLS) head gasket is built for serious performance. It's specifically designed for Chevrolet Mark-IV and GM Gen-V/VI Big Block V8 engines, and its 4.310-inch bore suits aftermarket heads, even featuring undersized water ports for custom porting. This gasket is a solid choice for high-output applications, fitting a wide range of GM vehicles from the 1960s through the 1990s, including popular models like the Chevrolet Impala, C10 Pickup, and Corvette.

The construction here is key to its sealing ability. Cometic uses multiple layers of stainless steel for strength and corrosion resistance, which also allows the gasket to rebound and maintain a seal under stress. The outer layers are embossed and coated with Viton, a heat-resistant rubber material that can handle tough sealing environments, high loads, and various surface finishes. This makes it suitable for pairing aluminum heads with either aluminum or cast iron blocks, as it can manage the shearing forces that arise from dissimilar metals. Because it's an MLS gasket, it doesn't require any additional sealants, simplifying installation.