S&S Cycle M8 Power Package - 4.320" Bore - 129ci - Black - 310-1399

Unleash incredible power from your 107" Milwaukee-Eight® engine with the S&S Cycle 129" Power Package engine performance kit. This comprehensive bolt-on upgrade transforms your M8, boosting displacement to 129" without requiring any case machining, making for a straightforward installation and a significant motorcycle engine upgrade.

Description

Designed for motorcycle enthusiasts seeking a substantial power boost, the S&S Cycle 129" Power Package delivers an immediate performance increase to your 107" M8 engine. This kit features robust 4.320" big bore cylinders paired with 11.0:1 forged pistons, engineered to deliver maximum horsepower and torque. The included S&S oil pump and cam plate system ensures superior lubrication, featuring independent scavenge sections for both the flywheel cavity and cam chest, complete with debris screens and a magnet to prevent contaminants from reaching the pump. This enhanced oil flow capacity and protection contribute to the longevity and reliability of your high-performance engine.

Installation is simplified with Quickee pushrods and pushrod tubes, alongside S&S premium tappets and hard-anodized, billet aluminum tappet cuffs for exceptional durability. The adjustable pressure relief valve allows for fine-tuning even after installation, providing flexibility for various riding conditions. The kit incorporates S&S valve springs, compatible with cams up to 0.605" lift, and the high-performance HPT496 cam, specifically designed for big bore applications. A multi-layered steel (MLS) head gasket ensures a robust, leak-free seal. Notably, this Harley-Davidson M8 big bore kit retains stock engine height, works with stock crankcases, and preserves your original engine serial numbers, making it a seamless and compliant bolt-on M8 power package. Compatible with both stock and S&S roller rocker arms, and first or second-generation stock valve springs, this kit is truly a comprehensive solution.

Features & Highlights

• Transforms your 107" M8 engine into a powerful 129" powerhouse with a bolt-on design, requiring no case machining for easier installation.
• Equipped with 4.320" big bore cylinders and 11.0:1 forged pistons, delivering a significant increase in compression and engine output.
• Features an advanced S&S oil pump/cam plate with independent scavenge sections, debris screens, and a cam chest magnet for superior lubrication and engine protection.
• Includes Quickee pushrods, premium tappets, and hard-anodized billet aluminum tappet cuffs for enhanced durability and simplified maintenance.
• Optimized with an HPT496 cam and high-performance conical valve springs (up to 0.605" lift) specifically engineered for big bore applications.
• Maintains stock engine height, works seamlessly with stock crankcases, and retains original engine serial numbers for a hassle-free upgrade.

Technical Specifications

• Type: Engine Performance Kit
• Product Name: Power Package
• Model: HPT496 Series
• Displacement: 129"
• Bore Size: 4.320"
• Compression Ratio: 11.0:1
• Cam Drive Type: Gear
• Cooling System: Oil Cooled
• Color/Finish: Black, Highlighted Fins
• Features: Chrome Pushrod Tubes
• Units: Kit
• Vendor Part Number: 310-1399