Cometic C9818 Copper Base Gasket Big Twin Thick - 3.625 1984-Up 2-Pack 005

The Cometic C9818 is a premium heavy-duty copper base gasket designed specifically for Harley-Davidson Big Twin engines from 1984 and newer. This 2-pack includes .005" thick copper gaskets with a 3 5/8" (3.625") bore diameter, providing superior sealing performance for high-performance and stock applications.

Key Features:

• Precision-manufactured from pure copper for excellent thermal conductivity and conformability
• 3.625" bore diameter fits Big Twin engines 1984-present including Evolution, Twin Cam, and Milwaukee-Eight
• .005" (0.005 inch) thickness for precise head gasket compression adjustments
• Multi-Layer Stopper (MLS) construction ensures reliable sealing under extreme pressure and temperature
• Sold as a 2-pack for convenience on V-Twin applications
• Ideal for use between cylinder and crankcase to fine-tune compression ratios

Cometic gaskets are trusted by professional engine builders and performance enthusiasts for their consistent quality and durability. The copper construction provides superior heat dissipation and conforms to sealing surfaces better than traditional paper gaskets, making them perfect for high-compression builds and racing applications.