S&S CYCLE Power Pack - Oil Cooled - M8 310-1104A

If you're running a big bore M8 and want real gains in displacement and horsepower without dismantling your entire engine, the S&S CYCLE Power Pack delivers bolt-on simplicity with race-proven performance. This kit combines a 4.25" bore with precision-engineered internals—forged pistons, an optimized cam, and a completely redesigned oil system—giving you the displacement increase you need while maintaining reliability under sustained high-RPM operation. Whether you're on the dyno or the street, you get the displacement of a much larger engine rebuild without the downtime of case work.

Key Technical Specifications:

• Bolt-on installation
• 4.250" bore diameter
• 11.1:1 compression ratio
• Forged piston construction
• No case machining required
• S&S 550 Cam included
• Billet aluminum oil pump/cam plate
• Increased flow capacity (feed + scavenge)
• Independent scavenge sections
• Debris screens on both pickups
• Magnetic cam chest protection
• Adjustable pressure relief valve
• S&S premium tappets
• Billet aluminum tappet cuffs
• Quickee pushrods
• Removable passage plugs
• Fits Harley-Davidson M8 engines
• MPN: 310-1104A