2018 – 2026 M8 SOFTAIL MODELS STAINLESS X-SERIES™ STANDARD 2-INTO-1 Exhaust

NOTE:  Lead times on Thunderheader exhausts is typically 6-10 weeks before they ship and there's a $75 surcharge for shipping expenses.

WE CANNOT SHIP TO CALIFORNIA.  SORRY. CARB IS LAME.

Our X-SERIES™ Exhaust in Stainless Steel is our newest line in creating maximum horsepower. With our 2″ head pipes, equal length tubes, and a larger collector, this exhaust is made specifically for Harley-Davidson’s Milwaukee-Eight™ engine. 18mm and 12mm O2 sensor ports.

Includes all clamps, bracket, and install hardware. MUST use Screamin’ Eagle Flat Gaskets to install properly (HD Part#17048-98).

Thunderheader exhaust systems are premium high-performance 2-into-1 exhausts designed to maximize horsepower, torque, and throttle response on Harley-Davidson motorcycles. Known for their race-proven design, Thunderheader exhausts deliver powerful low-end torque, strong mid-range acceleration, and consistent top-end performance.

Ideal for Harley-Davidson Touring models, M8 engines, baggers, Dyna, FXR, and Softail builds, Thunderheader exhaust systems are engineered for riders who demand real performance gains. Each exhaust features precision-welded construction, optimized collectors, and a distinct aggressive exhaust note trusted by racers and performance builders.

Whether you’re upgrading a street bike or building a performance-focused Harley, Thunderheader exhausts provide proven power, durability, and sound. Shop Thunderheader exhaust systems and take your Harley-Davidson performance to the next level.