Thrasher Upgrade Kits for Harley-Davidson Motorcycles

Call 800-841-STAR or E-mail for more information.

Our Thrasher series, engine packages are the most powerful and reliable available.



  • For 2007-2016 Harley-Davidson Models

  • (Also available on Twin Cooled)

  • New improved Head flow has offered even more power for the same money!!!!!

125 guaranteed horsepower with our Thrasher kit for your 103 bored to 107 with recommended components!


Call 800-841-7827 to make an appointment.


The 107” upgrades offered by Star Racing delivers more bang for your buck than any other upgrade on the market.

Our performance packages typically produce 130+ horsepower depending upon your current *exhaust system. 

Installation of the kit maintains the appearance of a stock engine, but you will definitely feel the difference! 

Finally, your bike will be the fastest and your buddies will be scratching their heads trying to figure out what you have done.


*When used with D&D Boarzilla exhaust.

Included in the package:

  • Cylinder Heads - Pro Ported & Machined

  • Oversized Valves - Intake & Exhaust

  • Bronze Alloy Valve Guides

  • Performance Valve Spring Kit

  • 635 Lift Cams

  • CP +6cc 10.8 to 1 pistons

  • Cylinders - Bored & Honed With Torque Plates

  • Adjustable Pushrods

  • MLS Head Gaskets

  • FBW 58 mm Throttle Body

  • Manifold Modified to Flow

  • S/E Clutch Upgrade

  • All Necessary Hardware

  • Fluids, Filter, & Plugs

  • FireCore Wires

  • Complete Labor

  • Before & After Dyno Test

  • Custom Dyno Map

Turn Key $5,795

Options to add to your Package:

Boarzilla Exhaust............starting at $1,200

TTS Tuner............$440

Bigger, Better Air Cleaner.............$399

These are options that work best with our Packages.

We have these as options because some folks already have these items. 

We use the TTS tuner or the Screaming Eagle Tuner.

Email for more info and details.

Turn around time is typically 3- 4 weeks for our Thrasher kits depending on shop workload, so you will be back on the road in no time!


WARRANTY - Star Power makes no warranty, expressed or implied, as to the products sold, manufactured, or imported by us, including without limitation any warranties or merchantability and fitness for a particular purpose. These parts are designed for racing only; use them at your own risk.

YOUR COMPLETE SATISFACTION IS OUR GOAL – Most performance parts are designed for off highway use only and may not be legal for use on public streets, roads, or highways. Performance parts are inherently short lived and must be inspected regularly to prevent untimely failure and/or damage. Any new or modified parts, or any services provided by Star Power (or which are sold through Star Power) are sold as performance parts and are sold as is with no warranty, unless specified by the individual manufacturer.