Cometic C9819 Copper Cylinder Base Gasket Set 3-5/8" Bore Harley Big Twin .010" 2-Pack

The Cometic C9819 is a premium copper cylinder base gasket set designed for Harley-Davidson Big Twin motorcycles from 1984 and up. This 2-pack contains heavy-duty copper base gaskets with a 3-5/8" (3.625") bore and .010" thickness, ideal for performance engine builds and rebuilds.

Key Features:

• Solid copper construction for superior heat dissipation and sealing
• 3-5/8" (3.625") bore diameter fits Big Twin Evolution and Twin Cam engines
• .010" (.254mm) thickness allows precise deck height adjustment
• Two gaskets included - one for each cylinder
• Ideal for fine-tuning compression ratio and piston-to-head squish clearance
• Engineered for high-performance and modified engines
• Made in USA with American-sourced materials

Cometic copper base gaskets are preferred by professional engine builders for their ability to conform to cylinder deck surfaces and provide a reliable seal in high-heat, high-compression applications. The .010" thickness is one of several available options that enable builders to precisely control cylinder deck height during performance engine assembly.