Cometic C9478 Top End Gasket Kit Big Bore Harley Evolution - 3.75 1100

The Cometic C9478 is a premium top end gasket kit designed specifically for 1986-1987 Harley-Davidson Evolution Big Twin 1100cc engines equipped with 3.75-inch (3-3/4") big bore cylinders. This comprehensive kit provides everything needed for a complete top-end rebuild or performance upgrade with advanced sealing technology.

Multi-Layer Steel (MLS) Head Gaskets: Features Cometic's renowned MLS head gaskets constructed from multiple embossed layers of stainless steel with high-temperature coatings. This advanced design provides superior heat dissipation and sealing capability compared to traditional single-layer gaskets, making them ideal for high-compression and performance applications.

Complete Kit Includes:

• MLS cylinder head gaskets for both cylinders
• Steel Viton-coated cylinder base gaskets
• Rocker box gaskets (upper, lower, and middle)
• Blue Viton valve stem seals for oil control
• Pushrod tube seals and O-rings
• Exhaust port gaskets
• All necessary seals and O-rings for complete top-end assembly

Advanced Materials: The kit utilizes embossed stainless steel gaskets with proprietary Viton rubber coatings that eliminate leakage when joining metal surfaces. The head gasket material draws heat away from the combustion ring and dissipates it evenly across the gasket surface to prevent hot spots and gasket failure.

Engineered for big bore applications, this gasket set is the perfect complement to performance cylinder kits and engine rebuilds. Made in the USA with precision manufacturing to ensure leak-free operation and maximum reliability in demanding conditions.