S&S CYCLE - 310-1225D - 129" Power Package - '17-'26 Harley-Davidson Street Glide Special, Heritage Classic 107, Softail Standard 107
S&S engineered this 129" Power Package to take a 107" M8 up to 129" of displacement as a bolt-on kit - no case machining needed - using 4.32" bore forged pistons at 11.0:1 compression for '17-'26 Harley-Davidson models. Its blue-anodized oil pump/cam plate runs independent scavenge sections for the flywheel cavity and cam chest, with debris screens and a cam-chest magnet protecting oil cleanliness, and increased flow capacity on both feed and scavenge sides.
Features
- Big-bore bolt-on kit increases 107" M8 to 129" with no case machining required
- 4.32" bore cylinders with 11.0:1 compression ratio forged pistons
- S&S oil pump/cam plate with blue anodized finish
- Passage plugs are removable for servicing
- Independent scavenge sections for flywheel cavity and cam chest
- Debris screen in both scavenge pickups
- Magnet in cam chest to help prevent debris from entering the oil pump
- Increased oil flow capacity on both the oil feed and scavenge side
- Adjustable pressure relief valve can be adjusted with the unit installed in the engine
- Quickee pushrods
- S&S premium tappets
- S&S hard-anodized, black coated tappet cuffs are billet aluminum construction
- S&S 550 cams are designed for big bore applications
- S&S valve springs work with cams up to 0.605" lift
- High-performance conical single wire spring design
- Made in the USA
- Will fit VVT models.
- Not for any Trike models.
- Intake/rocker cover gaskets not included.
Specs
- Color/Finish: Highlighted Fins
- Color/Finish: Wrinkle Black
- Compression Ratio: 11.0:1
- Features: Black Pushrod Tubes
- Units: Kit
- Product Name: Power Package
- Stroke Length: 4.375"
- Cam Drive Type: Chain
- Displacement: 129"
- Features: Cam Chain Tensioner
- Style: 550C
- Bore Size: 4.320"
- Riding Style: Street
- Cooling System: Oil Cooled
- Model: Performance Kit
Frequently Asked Questions - S&S CYCLE - 310-1225D - 129" Power Package - '17-'26 Harley-Davidson Street Glide Special, Heritage Classic 107, Softail Standard 107
How do I know if this part fits my vehicle?
Check the fitment information listed on this page against your exact year, make, model, and (where applicable) trim, engine size, or configuration. If your exact vehicle isn't listed, or you're not sure, use the product chat on this page or contact our support team before ordering - we're glad to help confirm fitment.
What does it mean if a product is listed as universal fit?
Universal fit means the product is designed to work across a range of vehicles, not that it's guaranteed to fit every one. Compare the listed measurements, mounting requirements, and connector or hardware specs against your specific vehicle before ordering, since some installations may need additional hardware or minor fabrication.
Where can I find installation instructions for this product?
General installation notes are provided above where available. For detailed step-by-step instructions, refer to the manufacturer's documentation included with the product, or use the product chat on this page for questions about difficulty, required tools, or whether professional installation is recommended.
What if I have more questions about this product?
Use the product chat on this page for fitment, specs, installation, and compatibility questions, or contact our support team directly for help before you order.
