Hennessey is celebrating its 25th birthday this year and what better way to mark the occasion than tune the heck out of a Ford Mustang GT!

The standard model with the mighty 5.0-litre V8 makes a very healthy 435 horsepower and 542Nm of torque. Best of all is that new Line Lock feature that allows you to smoke the rear wheels but if you try that in this HPE800, you’ll probably be down to the alloys in seconds.

Their latest creation makes a staggering 804 horses and 878Nm of torque. It can hit 100kph in just 3.1 seconds and has a top speed of 334kph. Yes, wow indeed. How has the Texas-based tuner gotten these mouthwatering figures? Well, the highlights include a 2.9-litre Whipple supercharger, carbon fibre high-flow air intake, axle-back exhaust system, and upgraded fuel injectors and pump. With all the extra power, it is reassuring to see that Hennessey also fitted the Pony with Brembo 15in brakes at the front. It rides on 19in (front) 20in (rear) lightweight alloys which have been wrapped in sticky Michelin Pilot Super Sport tyres. It also has a KW Variant 3 lowered suspension while the exterior features carbon-fibre aero aids including a new front splitter, rear spoiler, and side sills. That’s not all – Hennessey adds its own graphics package along with HPE800 designation to the rear decklid – and it’s also embroidered into the headrests. The tuner is including a limited edition serial numbered plaque and a Hennessey 25th Anniversary certificate of authenticity.

The HPE800 package will be made available on all combinations of the Mustang GT (coupe, convertible, automatic, or manual). Like what you see? So do we. Want one? Us too. But you’d better hurry as just 25 are going to be built.