S&S Cycle 106-4270 Super Stock 89cc Cylinder Head Kit Silver Powder Coat Twin Cam

The S&S Cycle Super Stock 89cc Cylinder Head Kit (106-4270) is a high-performance, fully assembled cylinder head set engineered to deliver immediate power gains and a strong foundation for future engine upgrades. Featuring a silver powder-coat finish designed to complement OEM components, these heads are sold in pairs and proudly made in the USA.

The 89cc combustion chamber delivers a slightly higher-than-stock compression ratio well-suited to larger displacement and big bore engine builds. High-flow intake ports flow an impressive 264 cfm compared to just 182 cfm on stock heads, delivering meaningful gains in low, mid, and top-end power. The large 2.000" intake and 1.605" exhaust valves maintain port velocity for strong low and midrange response while supporting the breathing needs of larger engines.

Key Features:

• 89cc combustion chamber — ideal for motors over 103" or with high-compression pop-up pistons
• Fully assembled with valves and high-performance valve springs supporting up to .640" cam lift
• Intake ports flow 264 cfm vs. 182 cfm stock
• 2.000" intake and 1.605" exhaust valve sizing
• Silver powder-coat finish matches OEM components
• CNC-machined for optional compression releases (sold separately)
• Accepts OEM intake manifolds
• Sold in pairs — Made in the USA

What's Included / Not Included:

• Includes: Cylinder heads with valves and springs (pair)
• Does not include rocker arm components, intake manifold, gaskets, or head bolts
• Requires eight long OEM-length head bolts for installation

Important Notes:

• S&S rocker boxes (Part #90-4110) are required if S&S electric compression releases are used
• Compression ratio varies depending on heads chosen, pistons used, and engine displacement
• Not legal for sale or use in California or on any EPA pollution-controlled motor vehicle