S&S CYCLE 129" Power Package Engine Performance Kit - Chain Drive - Oil Cooled - Non-Highlighted Fins - M8 310-1226

If you're running an M8 with 107 cubic inches, you're leaving serious power on the table. The S&S Cycle 129" Power Package transforms your engine into a genuine big-displacement performer without requiring case machining—a straightforward path to increased displacement, torque, and throttle response. This is a complete, engineered solution that respects your original engine's identity while unlocking measurable performance gains.

What sets this kit apart is S&S's attention to reliability and serviceability. The independent scavenge sections prevent oil starvation in the cam chest, the magnet captures ferrous debris before it reaches your oil pump, and removable passage plugs keep maintenance simple. You're getting a bolt-together upgrade that integrates seamlessly with your stock crankcase and retains your engine's original serial numbers.

• Displacement: 107" to 129"
• Configuration: Big-bore cylinders
• Cam: Performance-matched 550
• Lubrication: Oil-cooled design
• Drive: Chain drive
• Valve springs: High-performance conical single-wire
• Crankcase: No machining required
• Gaskets: Multi-layered steel (MLS)
• Scavenge: Independent flywheel and cam sections
• Debris protection: Magnet, screens in pickups
• Serviceability: Removable passage plugs
• Fitment: M8 Harley-Davidson models
• Origin: Made in the USA
• MPN: 310-1226