Screamin’ Eagle Milwaukee-Eight Stage IV Kit

Boost Horsepower by Up To 52 Percent Over Stock and Gain Stump-Pulling Torque

Tune a Harley-Davidson Milwaukee-Eight engine to the max with a potent new street-legal Screamin’ Eagle Milwaukee-Eight Stage IV Kit available now from Harley-Davidson Genuine Motor Parts & Accessories.

Delivering a boost in both displacement and air flow through the engine, these complete kits were developed to deliver maximum horsepower from the Milwaukee-Eight engine all the way to redline while retaining a high level of factory-engineered smoothness, ride quality and reliability.

“We’ve designed this amazing Screamin’ Eagle Stage IV kit for the performance fanatic,” said Harley-Davidson Senior Product Manager Scott Miller. “Big-bore cylinders, a monster throttle body, ported heads, and a high-lift cam combine to deliver stump-pulling torque throughout the rpm range and up to 52 percent more power than the stock Milwaukee-Eight engine.

“The Screamin’ Eagle Milwaukee-Eight Stage IV Kit is a system-matched collection of components created by the same Harley-Davidson engineering team that designed and developed the Milwaukee-Eight engine,” said Miller. “Upgrading the engine with genuine H-D parts supports a performance gain without sacrificing warranty, drivability or reliability. There are no compromises.”

milwaukee 8 screamin eagle stage 4 kit

Factory-Engineered Components

Courtesy of Harley-Davidson

Screamin’ Eagle Milwaukee-Eight ported cylinder heads are a key component of the Screamin’ Eagle Milwaukee-Eight Stage IV Kit. Based on a unique Screamin' Eagle casting, these cylinder heads optimize air/fuel flow when paired with a Screamin’ Eagle 64mm throttle body.

The ports are meticulously machined on a five-axis CNC machine to increase the volume and velocity of the intake charge for improved efficiency of cylinder filling and to maximize the effect of exhaust scavenging. The Screamin’ Eagle ported heads are equipped with high-performance valve springs that remain stable with high-lift cams in high-RPM operation. The SE8-515 camshaft, designed in conjunction with the Screamin’ Eagle Milwaukee-Eight Stage IV Kit, offers a high-lift and long-duration profile to efficiently fill the combustion chamber and retain 50-state street-legal emissions compliance. Screamin’ Eagle 4.075-inch bore bolt-on cylinders and matching pistons increase displacement of Milwaukee-Eight 107 engines to 114 cubic inches, and take Milwaukee-Eight 114 engines to 117 cubic inches. The Screamin’ Eagle Milwaukee-Eight Stage IV Kit can be installed without removing the engine from the chassis.

Complete Screamin’ Eagle Milwaukee-Eight Stage IV Kit components include:

  • Screamin’ Eagle CNC Ported Cylinder Heads with Performance Valve Springs

  • Screamin’ Eagle 64mm Throttle Body

  • Screamin’ Eagle High Flow Injectors (5.5g/s)

  • Screamin’ Eagle 4.075-inch Bolt-On Cylinders

  • Forged 11:1 High Compression Aluminum Coated Pistons

  • High Performance Piston Rings

  • SE8-515 Cam

  • Screamin’ Eagle Cam Bearing Upgrade

  • Screamin’ Eagle High Performance Tappets

  • Multi-layer Coated Head Gaskets

  • Top End, Cylinder Base and Cam Cover Gaskets

  • Screamin’ Eagle High Capacity Clutch Springs and Plates

milwaukee 8 screamin eagle stage 4 kit

Screamin’ Eagle Milwaukee-Eight Stage IV Kit

Courtesy of Harley-Davidson

There are three Screamin’ Eagle Milwaukee-Eight Stage IV Kit options:

milwaukee 8 screamin eagle stage 4 kit

107 stock vs 107 to 114

Courtesy of Harley-Davidson

To achieve maximum performance, match a Screamin’ Eagle Milwaukee-Eight Stage IV Kit with a Screamin’ Eagle high-flow intake and exhaust upgrade, like the new Screamin’ Eagle High Flow Exhaust System (P/N 64800059 Chrome, $1,299.95; P/N 64800062 Satin Black, $1,399.95*) and the Screamin’ Eagle Ventilator Air Cleaner (P/N 29400298 Gloss Black, P/N 29400299 Chrome; $299.95). When installed by an authorized Harley-Davidson dealer at the time of vehicle delivery, the Original Equipment Factory Warranty is retained. This kit is 50-state U.S. EPA compliant. The Screamin’ Eagle Milwaukee-Eight Stage IV Kit does not fit Trike models. Installation requires separate purchase of Cam Drive Retention Kit P/N 25566-06 and may require Cam Spacer Kit P/N 25928-06. All models require ECM calibration with Screamin’ Eagle Pro Street Tuner for proper installation. See an authorized Harley-Davidson dealer for details.

milwaukee 8 screamin eagle stage 4 kit

114 stock vs 114 to 117

Courtesy of Harley-Davidson

These and other Harley-Davidson Genuine Motor Parts & Accessories are available at more than 750 authorized retail locations in the United States and online.

About Harley-Davidson Motor Company

Since 1903, Harley-Davidson Motor Company has fulfilled dreams of personal freedom with cruiser, touring and custom motorcycles, riding experiences and events, and a complete line of Harley-Davidson motorcycle parts, accessories, general merchandise, riding gear and apparel. For more information, visit