The Hennessey ‘Super Venom’ is an 850bhp upgrade for the Mustang GT and Dark Horse

Hennessey has done that thing again where it takes a fast car and makes it even faster, subjecting the Ford Mustang GT and Dark Horse models to outrageous amounts of power. New total? That’ll be around 850bhp - 46 more than the ‘Ring record-setting GTD - plus 650lb ft.

Customers can choose a base GT or Dark Horse model from a Ford dealer, who’ll then give them the option of fitting this ‘Super Venom’ package on top. It includes a wheezier supercharger, new injectors and an improved induction kit, which in the case of the Dark Horse, combine to shave half a second off the 0-60mph time (now 3.2s), and over a second off a standing quarter-mile run. Naturally, the GT version will be slightly slower than this.

If you were to opt for the Dark Horse, you’d also gain the bits that remain an optional extra on the GT, such as an active exhaust, limited-slip differential and adaptive damping. The choice of swapping a standard 10-speed manual for a traditional six-speed stick remains.

But cosmetically, there will be very little to separate the two cars. Hennessey has crafted a new carbon fibre aero kit, comprising a much angrier front splitter, vented bonnet and fixed gooseneck rear wing. You’ll get 20in lightweight performance wheels and lots of Super Venom badging too. OK, so the latter is unlikely to contribute to better aero, but at least it looks cool.

The interior also gets a sweep, including leather and Alcantara-fied upholstery for the Recaro seats and a bespoke dashboard plaque with a build slot number. Yep, the Super Venom package will be limited. Very limited, actually, to just 91 units in commemoration of the American tuner’s founding year of 1991.

Pricing is set at $163,950 for the Dark Horse and $149,950 for the GT, which is respective of the cost difference between the standard Ford versions of the two models. So, one of these or a GTD?