S&S Cycle 91cc Cylinder Heads - Harley Dyna

These S&S Cycle cylinder heads are designed for Harley-Davidson Dyna 91cc engines, providing increased flow and combustion efficiency over OEM castings. They are a direct bolt-on replacement, optimized for high-performance builds seeking improved breathing and power from their V-twin.

Why riders pick this

• Increased flow over stock cylinder heads
• Direct bolt-on replacement for Dyna 91cc engines
• Silver finish matches engine aesthetics
• Optimized for improved breathing and power

Maximizing the power output of your Harley Dyna often comes down to how efficiently your engine can breathe. These S&S Cycle cylinder heads are engineered to surpass the flow characteristics of stock castings, allowing your 91cc Dyna engine to inhale and exhale more effectively. This improvement in gas exchange directly translates to enhanced combustion efficiency and a noticeable boost in overall performance, making them a cornerstone for any serious engine build.

Enhanced Flow for Dyna Performance

• Engineered for increased flow and combustion efficiency over stock heads
• Direct bolt-on replacement for Harley-Davidson Dyna 91cc engines
• Silver finish for a clean, factory-like appearance
• Optimized to improve breathing and power output

Building a Balanced Powerplant

While these S&S Cycle cylinder heads offer significant improvements on their own, the greatest gains in horsepower and torque are realized when they are integrated into a comprehensive performance package. Pairing these heads with a complementary intake system, a free-flowing exhaust, and a custom fuel management tune will unlock the full potential of your Dyna engine. Always verify valvetrain geometry, especially when combining new heads with other performance components, to ensure proper clearance and operation.

Specifications

• Brand: S&S Cycle
• Manufacturer Part #: 900-4278
• Weight: 1 lb
• Finish: Silver
• Category: Engine Components / Heads

Common questions