Test Riding Harley’s Largest, Most Powerful Engine Ever in a 2024 Road Glide
The staff at Blockhead Moto take turns thrashing Harley’s new 135 c.i. crate engine
I don’t know about you, but nothing like this ever happens at my day job. That is, after shoehorning a bold new 135 cubic inch crate engine into a 2024 Road Glide that costs $26k in stockform , your boss almost forces you to take it our for a 100 mph joy ride. But that’s exactly what happened to the lucky staff at Blockhead Moto, the shop behind the successful BLOCKHEAD YouTube channel.
The engine in question is Harley-Davidson’s new Screamin’ Eagle Stage IV Milwaukee 8 with a whopping 135 cubic inch (2.2 liters using the metric system) displacement. That’s larger than many modern car engines. What all those cubic inches gets you is 144 horsepower and 149 foot-pounds of torque. Better still, those figures are measured at the rear wheel, not just unburdened at the crankshaft. In another recent video, Blockhead actually dyno tested this $7,995 crate engine and the results were even better than advertised by a small margin.
The Stage IV 135 crate engine in Blockhead’s bike is liquid cooled. That’s perfect for the muggy Florida weather where the shop is located. Although water cooling Harleys might be blasphemy to some, we have to admit that it’s well executed and as discreet as possible.
Taking it to the streets
After the 2024 Road Glide’s stock powerplant was replaced with the 135 c.i. beast, the first test pilot is Jon, the proprietor of Blockhead Moto. His first reaction is that it’s like re-learning how to ride the Road Glide all over again. Per Jon, “It’s so different. It’s a brand new bike, right?” Jon continues, “It feels totally different than the bike you just got off of that you learned and you have to relearn it.”
After a second gear start, it’s clear that the big Road Glide would pull the front wheels in the air bigly if you’ve got the huevos to peg the throttle in first gear instead. On the highway, the Stage IV crate engine just freight trains from 70 to 100+ mph, even in sixth gear. Which is the other great thing about this motor: its powerband is as wide as the Grand Canyon. You don’t need to continuously shift up and down to keep it in a sweet spot. The entire RPM range is the sweet spot.
Next up is Blockhead’s video editor, Justin James. Justin is nervous about riding a touring bike because of his five-foot-two-inch stature, but that fear was unwarranted. Besides the insane power, he loved the fairing for its wind buffeting and brace of digital gauges and GPS display. Finally, Blockhead technician Chris puts the big Road Glide’s wheelie chops to the test and comes away impressed.
Expect more mods to the 135 crate engine
According to Blockhead’s Jon, the 135 crate engine-powered Road Glide is actually part of a build-off versus Kruesi Originals in Arizona. Therefore, the gonzo powerplant is just the tip of the modification iceberg. Without revealing too much, we learn that the build-off bike will get an in-house designed and manufactured exhaust system. Instead of the current Screamin’ Eagle headers and aftermarket slip-on mufflers that exit the rear, the new bespoke exhaust will exit the side. Supposedly, it’ll be chill during highway cruising, but loud when you want it to be.
A perhaps more crucial mod is a new clutch and basket from Rekluse for withstanding the extra horsepower over the long-term. There’s no doubt that the factory clutch would get smoked in short order, especially riding like this crew. As far as the rest of the customization plan to hopefully beat Kruesi Originals, you’ll just have to stay tuned.
Photos: BLOCKHEAD/YouTube
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