Hennessey supercharges Mustang Dark Horse to 850hp

There isn't much V8 muscle left - Hennessey is making the most of it 

There are many reasons why the Mustang Dark Horse might appeal, from its Tremec six-speed manual gearbox (where a GT must make do with a Getrag) to its 500hp, the gnarly new look to the track-ready suspension. Even in slightly diluted form with less power and no Handling Pack option, the prospect of the Dark Horse in the UK is an exciting one. Over in the US, however, as well as the full stallion spec from factory, Hennessey has already supercharged the Dark Horse. Indeed it’s in production already - you probably don’t need to be told what H850 denotes. 

That’s good ol’ boy imperial horsepower, too, not the metric stuff used by the supercar makers. In new money it’s 862hp, which is more than the new Ferrari 12Cilindri (and a 296 GTB) as well as what’s coming from Lamborghini’s new V8. Even in a world of massive horsepower, that’s a tremendous amount for a Mustang.

Best of all, Hennessey’s work should retain a lot of the Dark Horse’s GT500-influenced character, still making peak power at 7,250rpm - or just 250rpm short of the redline. The leap from 419lb ft to 650lb ft will surely transform the experience just as obviously. Long live forced induction torque. 

In addition to the ‘charger, Hennessey’s H860 upgrade gets uprated injectors and a better fuel pump to feed what’ll now be an even hungrier V8, and some ECU manipulation to get all the hardware in agreement. Plus make more power. In fact, this is 70 per cent more potent than standard, yet today’s release makes no mention of chassis changes beyond a Performance Wheel Package. Standard Dark Horse must be good. 

And who cares about chassis when you live your life a quarter mile at a time? This is a 10-second Mustang, amazingly enough, recording a 10.9 at 133mph in Hennessey’s testing with the ten-speed auto. That terminal speed was 15mph up on stock. Hennessey is keen to highlight how the H850 offers ‘serious bang for buck alongside supercar-like performance and the glory of a supercharged V8 soundtrack’, and while fast cars are about more than just sheer speed, those numbers are pretty emphatic. 

Having been announced last year, the H850 is now being made at Hennessey’s Texas HQ, complete with a three-year/36,000-mile warranty. It’s even available through certain, authorised Ford retailers. Expect to pay around $50k on top of a normal car. John Hennessey said: "Our supercharged H850 Mustang Dark Horse builds on Ford’s commitment to provide automotive enthusiasts with passion products like the snarling V8-powered S650 Mustang. We’re excited to unleash Hennessey’s passion for performance on America’s most iconic muscle car with all the sights, sounds, smells, and sensations that get our blood pumping!” Amen to that.

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