S&S Cycle 90-1106 Super Stock 89cc Twin Cam Cylinder Head Kit - .640in. Lift Springs

The S&S Cycle Super Stock 89cc Cylinder Head Kit (part #90-1106) delivers a significant upgrade in airflow and performance over stock Twin Cam cylinder heads. Featuring an 89cc combustion chamber, these heads provide a slightly higher-than-stock compression ratio that remains manageable even in larger-displacement builds, making them an excellent choice for heavily loaded touring bikes and other high-demand applications.

Key Features:

• Fully assembled with valves and high-performance valve springs — ready to install out of the box
• Large 2.000" intake and 1.605" exhaust valves maintain strong port velocity for excellent low and midrange torque while supporting the airflow demands of larger engines
• 264 CFM intake port flow — a dramatic improvement over the stock head rating of 182 CFM
• High-performance valve springs support camshaft lift up to .640"
• Machined to accept S&S compression releases (sold separately); requires S&S rocker boxes (Part #90-4110) if S&S compression releases are used
• Compatible with OEM intake manifolds and stock rocker boxes (when S&S compression releases are not used)
• Includes four long head bolts; four additional long OEM head bolts are reused
• Does not include rocker arm components, intake manifold, or head gaskets
• Sold in pairs (front and rear)
• Made in the U.S.A.

Compression ratio varies depending on the combustion chamber chosen, pistons used, and engine displacement. Head gaskets are not included, allowing builders to fine-tune compression ratio by selecting the appropriate gasket thickness. Cross-reference part numbers: Drag Specialties #0930-0006, Tucker #493649.

Note: Not compatible with Twin Cooled cylinder heads. Not legal for sale or use in California on pollution-controlled motor vehicles.