If you find the 2025 GMC Yukon Denali’s optional 420-horsepower 6.2-liter V-8 a bit underwhelming, but don’t want to take on the badge snobbery of a Cadillac, Hennessey has your fix. To the tune of 600 hp, to be exact. Meet the Hennessey H600, the ultimate Yukon Denali, literally.
Doing what it does best, the Texas-based tuning firm cranks up the power a few notches on the already pretty potent Yukon Denali, thanks to a whole list of under-the-hood upgrades. But more so, it gives buyers the chance to spring for a more powerful GMT T1 truck without having to make the giant leap for a nearly 700-hp Escalade V.
Escalade V-Like Supercharged Power Without All The Excess
Like many of Hennessey’s truck upgrades, the H600 starts life as your typical short-wheelbase 2025 GMC Yukon Denali, complete with its standard 6.2-liter EcoTec3 “L87.” That means 420 hp and 460 pound-feet of torque. In the event that’s not enough, however, Hennessey adds its signature 3.0-liter supercharger to the L87.
Should you also care just as much about stopping as going fast, Hennessey even says it’ll offer the H600 with an optional performance wheel and big-brake package.
To bolster the extra induction, the firms engineers also upgrade the engine with a higher-flowing air induction system, along with a high-flow heavy-duty intercooler to help condense that intake air, upgraded chromoly pushrods, a freer flowing crankcase ventilation system, and Hennessey’s proprietary recalibrated engine management software. And the result is a total output of 600hp and an unspecified amount of torque.
It might not be as potent as an Escalade V’s 682 hp and 653 lb-ft of torque. But not everyone needs that sort of bonkers power, as the Hennessey H600 slots in between the stock Yukon Denali’s 420 hp and the Escalade V’s nearly 700-hp figures.
Hennessey didn’t provide any performance figures. But considering the stock Yukon Denali takes about six seconds to hit 60 MPH, while the Escalade V does it in under 4.5 seconds, it’s save to assume the Hennessey H600 will crack the same sprint in around five seconds or so.
As we know from other Hennessey packages, they just don’t slap on a bunch of upgrades without considering all the other factory pieces that might not be up to specification to handle the extra boost. As such, Hennessey also takes the extra steps to make sure its upgraded L87 gets the proper fluids and upgraded hardware and gaskets to support the additional power. And to remind anyone of what lurks under the hood for those who pop it, all H600 V-8s come with a serialized engine plaque.
Hennessey does also admit its custom engine management does away with the 6.2-liter’s clever fuel-saving cylinder deactivation and automatic engine start/stop system. But when you’re after 600 hp in a leviathan, are you really concerned about saving gas?
It’s then all dyno-tested for proofing and road-tested for an additional 500 miles to ensure everything’s working as promised. And the best part: it still comes with a 3-year/36,000-mile limited warranty.
Should you also care just as much about stopping as going fast, Hennessey even says it’ll offer the H600 with an optional performance wheel and big-brake package. The company didn’t reveal any specific pricing for the updated 2025 model. However, given that a standard Yukon Denali Ultimate starts at $101,795 without shipping, it ain’t going to be cheap.
Read the full article here