S&S CYCLE Cylinder Heads 106-4277

S&S Cycle cylinder heads deliver measurable flow improvements that enhance performance immediately while laying the foundation for future engine modifications. Whether you're running a stock 88" big twin or pushing displacement north of 103", these fully assembled heads eliminate guesswork with purpose-built chamber volumes and valve configurations. Machined for compression releases and manufactured domestically, they're built to handle serious horsepower gains without compromise.

• Fully assembled with springs, valves
• 79cc: 1.940" intake / 1.575" exhaust
• 89cc: 2.000" intake / 1.605" exhaust
• Valve lift capacity: .640"
• 79cc: stock 88–103" displacement
• 89cc: 103"+ or high-compression pistons
• Compression release machined
• Four long headbolts included
• Reuses four OEM long bolts
• Accepts OEM intake manifolds
• Requires S&S rocker boxes (if using compression releases)
• Rocker arm components not included
• Made in U.S.A.
• Incompatible with Twin Cooled