My Account
My Garage
Shopping Cart

Shopping Cart

0 items in your Cart
View Cart
Subtotal
Track
My Order
MY GARAGE Select Vehicle
MY GARAGE

S&S Cycle 310-1058D 124" Gear Drive Power Pack for M8 107" Oil-Cooled Models

Manufacturer

Picture for manufacturer S&S Cycle

Part Number

310-1058D
7 reviews
Sale Price

$3,497.95

Estimated ship date Saturday, November 21

Check out with

ApplePay
Authorize Seller Badge
No Hassle Returns

No Hassle Returns

Live-in-stock inventory

Live-in-stock inventory

Fitment guaranteed

Fitment guaranteed

Product Details

The S&S Cycle 310-1058D is a 124" Gear Drive Power Pack engineered for Harley-Davidson Milwaukee-Eight (M8) models originally equipped with the 107" oil-cooled engine. This comprehensive big bore upgrade kit delivers a significant displacement increase and is designed for riders seeking a serious stage 4-level performance transformation. Cylinders feature a wrinkle black finish with highlighted fins, and the kit includes black pushrod tubes for an aggressive, blacked-out look.

Key Features:

  • Increases displacement to 124 cubic inches from the stock 107" M8 engine
  • Gear drive cam system for reliable, precise cam timing
  • Wrinkle black cylinder finish with highlighted fins
  • Black pushrod tubes included
  • Engineered for oil-cooled M8 Touring (FLH/FLT) and Softail platforms
  • Stage 4 performance level big bore upgrade
  • Comprehensive power pack bundle — combines cylinders, pistons, cam components, and related hardware

Installation Notes:

  • Installation should be performed by an experienced mechanic with access to a factory service manual and proper tooling
  • Measure flywheel pinion shaft runout and end play before installation — excessive runout or end play will void the manufacturer warranty
  • Recommended crankshaft runout: at or below 0.003"; ideal end play: 0.003"–0.004"
  • An aftermarket fuel management system (such as a ThunderMax Autotune) is strongly recommended
  • Not recommended for three-wheel trike models or trike conversion applications

The S&S Cycle 310-1058D Power Pack is a top-tier big bore solution for M8 owners looking to maximize displacement and performance while maintaining the reliability and fitment precision that S&S Cycle is known for.

Fast easy service just what I look for

Well-designed website and search, prices and checkout experience was nice.

The only problem was confusion with process and delivery information. And the picture of the generator wasn't what my pump was for. Despite that, it was right product delivered as fast as Amazon which brought me comfort to the confusion. Thanks for your service.

Shipping was fast and efficient! Very happy that the fuel pump I ordered was available and arrived in perfect condition. This was a quality fuel pump that was difficult to find and was very pleased with the procurement of my order. I will use THMotorsports again! Thank you.

I was charged $9.99 for shipping even though the ad stated free shipping...i was refunded $9.99 BUT i still paid tax on that $9.99 that i was not refunded. Other than that everything was all good...the megan racing muffler looks and sounds great!!! I wanted a muffler that wasnt obnoxiously loud but louder than stock and thats exactly what i got....AND the construction of the muffler is definitely good quality!!

Great

exactly what I wanted

Share icon
Return Policy
Returns are easy at Autoplicity

Not happy with a purchase? No problem. We've made returning items as easy as possible. And most purchases can be returned for free for 30 days. Learn more about our Returns Policy