S&S Cycle 129″ Power Pack For Harley With 107″ Milwaukee-Eight 2017-2026
S&S Cycle 129″ Power Pack: Mastering the Milwaukee-Eight Performance Standard
The S&S Cycle 129″ Power Pack for Harley-Davidson Milwaukee-Eight 107″ (2017-2026) represents the pinnacle of high-displacement architecture for the serious M8 enthusiast. For the rider of a Touring model who values the precision of a competition-grade “Big Bore” signature as much as long-term structural durability, the challenge has always been finding a conversion kit that bridges the gap between raw, explosive power and elite factory-integrated reliability. The 129″ Power Pack addresses these concerns by providing a complete, precision-matched foundation, designed to maximize compression stability and thermal dissipation. This design provides secure, mechanical utility by utilizing a refined, large-bore cylinder and forged piston geometry, effectively providing a high-output handling delivery that prevents thermal fatigue and optimizes torque delivery during high-velocity urban runs and aggressive highway sprints. This provides the mechanical synchronization of valve timing and elite internal combustion management needed to keep the rider confident, maximizing the efficiency of your performance run.
Material Innovation and Industrial Precision
What sets the S&S Cycle 129″ Power Pack apart in the marketplace is the uncompromising focus on structural stability and metallurgical durability. In the high-performance M8 touring scene, engine integrity is paramount; however, this system features a robust, precision-machined assembly that ensures the engine remains pressurized perfectly without compromising the integrity of the critical bottom end over years of heavy-duty use. The finish is engineered for secure, long-lasting aesthetic appeal, providing a high-output, uniform surface that resists oxidation and harsh environment wear. Every unit is manufactured to exacting tolerances, featuring precision-machined coolant passages and oil galleries for secure, leak-free installation on all Milwaukee-Eight 107″ touring frames from 2017 through 2026. Whether you are navigating technical city streets or cruising through mountain passes, S&S ensures your M8 Touring bike remains synchronized by professional-grade engineering integrity.
S&S Cycle 129″ Power Pack Technical Specifications
- Compatibility: Fits 2017-2026 Milwaukee-Eight 107″ Touring models.
- Displacement: Massive 129 cubic inch conversion for unrivaled torque.
- Components: Includes big-bore cylinders, forged performance pistons, and precision valvetrain components.
- Performance: Engineered for optimized compression, volumetric efficiency, and thermal management.
- Installation: Precision-engineered kit format for total mechanical synchronization with factory cases.
- Durability: Designed to withstand extreme high-output demands and engine vibration.
- Compatibility: Perfectly suited for elite performance builds demanding massive street-legal power gains.
Expert Fitment & Performance Advice
As specialists in motorcycle engine ergonomics, we recommend the S&S 129″ Power Pack for any build where “performance-oriented power” and “professional-grade touring capability” are the mission priorities. Pro Tip: To achieve your perfect setup, ensure your fuel system, clutch, and exhaust are upgraded to match the increased airflow and torque requirements; the secure mechanical balance is vital for maintaining a confident, high-power output during touring sessions. Installation Note: This kit is specifically designed to accommodate factory clearances for total chassis synchronization of your high-output powerplant. Maintenance Note: Regularly inspect your oil and cooling systems to maintain the high-output mechanical integrity and protect the engine from thermal degradation. Performance Note: Always verify that all engine bolts are torqued to a secure, mechanical specification to ensure the system performs as designed during a high-speed touring scenario.
The Professional Standard for Premium Performance Integrity
Choosing the S&S Cycle 129″ Power Pack means investing in unmatched mechanical stability and a refined engineering signature. It offers a unique combination of modern metallurgical science and bold design that honors the performance legacy of the S&S brand. For the rider who wants a high-output presence and a flawless engineering finish, S&S is the unmatched leader. Secure the ride, master the road, and ride with confidence.
| Product Style | AmericanV-twin Item # | Catalog Number | Store Sku | MFR. Product # | Availability |
|---|---|---|---|---|---|
| Black w/ Highlighted Fins / Chrome Pushrod Tubes / Chain Drive | 55220 | 55220 | 310-1223C | In Stock: Ships within 24 hours | |
| Black w/ Highlighted Fins / Black Pushrod Tubes / Chain Drive | 55221 | 55221 | 310-1225C | In Stock: Ships within 24 hours | |
| Black w/ Non Highlighted Fins / Black Pushrod Tubes / Chain Drive | 55222 | 55222 | 310-1226C | In Stock: Ships within 24 hours | |
| Black w/ Highlighted Fins / Chrome Pushrod Tubes / Gear Drive | 55223 | 55223 | 310-1224C | Only 5 Left: Ships within 24 hours | |
| Black w/ Highlighted Fins / Black Pushrod Tubes / Gear Drive | 55224 | 55224 | 310-1227C | In Stock: Ships within 24 hours | |
| Black w/ Non Highlighted Fins / Black Pushrod Tubes / Gear Drive | 55225 | 55225 | 310-1228C | In Stock: Ships within 24 hours |
This Product Fits
Harley Davidson
Electra Glide Standard FLHT 2019, 2020, 2021, 2022
Electra Glide Ultra Classic FLHTCU/I 2017, 2018, 2019
Road Glide 3 FLTRT 2026
Road Glide CVO ST FLTRXSTSE 2024, 2025, 2026
Road Glide FLTRX 2017-2026
Road Glide Limited FLTRXL 2026
Road Glide Special FLTRXS 2017, 2018
Road King FLHR/I 2017-2022
Road King Special FLHRXS 2017, 2018
Softail Breakout FXBR 2018, 2019
Softail Deluxe FLDE 2018, 2019, 2020
Softail Fat Bob FXFB 2018, 2019
Softail Fat Boy 114 FLFBS 2018, 2019, 2020, 2021, 2022
Softail Fat Boy FLFB 2018, 2019
Softail Heritage Classic FLHC 2018, 2019, 2020, 2021
Softail Low Rider FXLR 2018, 2019, 2020
Softail Slim FLSL 2018, 2019, 2020, 2021
Softail Sport Glide FLSB 2018, 2019, 2020, 2021
Softail Standard FXST 2020, 2021, 2022
Softail Street Bob FXBB 2018, 2019, 2020
Street Glide CVO ST FLHXSTSE 2026
Street Glide FLHX/I 2017-2026
Street Glide Special FLHXS 2017, 2018








