S&S Cycle Cylinder Heads — Harley-Davidson Dyna Wide Glide, Dyna Low Rider, Dyna Super Glide (1983-2020)

S&S Cycle cylinder heads for Harley-Davidson Dyna 91cc engines, engineered to increase flow and combustion efficiency over OEM castings. Direct bolt-on replacement designed for high-performance builds seeking improved breathing and power.

Features

• Increased flow over stock heads
• Direct bolt-on replacement
• Silver finish
• Optimized for 91cc displacement

Specifications

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

Fitment

Fits Harley-Davidson Dyna 91cc engines as a direct replacement for stock cylinder heads.

Frequently Asked Questions

Are these a direct bolt-on for my Dyna?

Yes — these heads are engineered as a direct replacement for Dyna 91cc stock castings with no modification required.

Will these heads alone increase my horsepower?

Heads improve breathing and combustion efficiency. Maximum gains come when paired with matching intake, exhaust, and fuel management tuning.

Do I need new pushrods or rocker arms?

Check with S&S or your builder — some head modifications may require valvetrain geometry verification to ensure clearance and proper geometry.

What's the weight difference from stock?

S&S heads weigh 1 lb each. Stock Dyna heads are heavier, so this is a slight weight savings per head.