How Much HP Does Harley-Davidson's Screamin' Eagle Stage IV Performance Crate Engine Have?

Crate engines are a lifeline for street-performance two-wheelers and four-wheelers. When Harley-Davidson introduced the Screamin' Eagle 135ci Stage IV Performance Crate Engine in 2023, it wasn't just a minor power bump –- but a revolution for motorcycle performance. In their own words, this street-compliant crate engine is "the biggest and most powerful" they've ever produced. And if you know anything about staunch Harley-Davidson enthusiasts, having a bigger, louder, and more powerful engine adds to their "badge of honor." As you'd imagine, Harley-Davidson's most powerful motorcycle engine was designed for riders looking for brute power and acceleration.

The Screamin' Eagle Stage IV Crate Engine pumps out a staggering 130 hp and 143 lb-ft of torque at the rear wheels, making it the most potent production engine from the Milwaukee-based motor company. Still, this crate engine isn't just about raw figures on paper – it's a nod to street performance culture, and a bold step pushing the limits of what's possible on a "Hog".

There's a big debate among motorsports aficionados on displacement and power, and the Screamin' Eagle 135 engine makes a great case study for the old motoring saying, "there's no replacement for displacement." At 135 cubic inches (2,212cc), this is the largest displacement street-use crate engine out of Harley-Davidson. It's nearly 25% larger than the base Milwaukee-Eight 107 engine, producing 28% more torque and 41% more horsepower than the production Milwaukee-Eight 117.

If you are going to make the most powerful engine for a respected motor company like Harley-Davidson, it'll need to ride like it belongs on a race team. As such, the Screamin' Eagle 135ci Stage IV Performance Crate engine is designed to run with a wide-open throttle, hitting those high RPMs. This crate engine shares some go-fast high-performance goodies with its 131ci sibling, such as Screamin' Eagle Extreme CNC-ported cylinder heads for airflow and combustion efficiency, high-performance cam bearings and tappets, SE (Screamin' Eagle) 517 high-lift camshaft, and 10.7:1 high-compression forged pistons. Add that to a 68mm throttle body and a high-flow intake combo, and it makes a lot of sense why this engine is able to achieve tons of power. 

With these high-performance bits, the Screamin' Eagle 135 engine makes 28% more torque than its predecessor. While it's designed to pack enough heat for the track, this Harley-Davidson crate engine is tuned for the streets. In fact, it is 49-state legal, meaning hog enthusiasts can enjoy big power while still meeting emissions compliance.

The Screamin' Eagle 135 engine wasn't designed for casual Sunday riders. With an engine that offers quick throttle response, brutal acceleration, and track-level output, this crate engine was developed for enthusiasts who love serious touring and big power. While anything goes when it comes to Frankenstein builds, this crate engine was designed for 2021 and later Touring models with oil-cooled Milwaukee-Eight Engines, and packs everything from upgraded injectors to cylinder heads. If you keep the warranty spec, the biggest benefit is that you'll get Harley-Davidson's 2-year covered care if it's installed within 60 days of purchase. 

As you might imagine, the Screamin' Eagle 135 engine isn't cheap, and it is priced at about $8,150  excluding installation. Still, it's a premium upgrade that radically transforms your bike into a track-level street-compliant hog. This crate engine is an upgrade to the front line of Harley-Davidson performance, offering 130 hp and 143 lb-ft of torque while still staying street-legal.