When Ford revealed the latest version of the Mustang Shelby GT500 a few years back, it came with the most power-dense supercharged V8 ever installed in a production car. It churns out up to 760 bhp (567 kilowatts) and 625 pound-feet (847 Newton-metres) of torque in standard form.

But Hennessey Performance takes that further with its flagship Venom 1200 upgrade. The Texas tuner was able to squeeze out a 58 percent boost over the factory engine output, making this Mustang one of the most powerful muscle cars Hennessey Performance has ever produced.

Gallery: Hennessey Venom 1200 Mustang GT500

The Venom 1200 upgrade on the stock Ford Mustang Shelby GT500 comes with a higher capacity 3.8-litre supercharger, a high-flow induction system, new fuel rails and injectors, and an air/oil separation system. Moreover, upgraded fittings, lines, belts, and tensioners are part of the package, as well as the recalibrated flex fuel engine and dual-clutch transmission to cater to the hypercar level of power output.

The result? The Hennessey Venom 1200 Mustang GT500 now makes 1,204 bhp (898 kW) and 902 lb-ft (1,223 Nm) of torque on E85 or race fuel, calibrated through Hennessey’s in-house dynamometer before being road-tested. The previous Hennessey-tuned Mustang GT500 we've seen only made up to 1,000 horses.

Apart from the engine upgrades, the Venom 1200 Mustang GT500 also comes with unique exterior badging and a special serial-numbered plaque. Of note, only 66 units will ever be built by Hennessey Performance with a starting price of $59,950 (approx. £51,600) accompanied by a comprehensive 1-year/12,000-mile warranty.

Meanwhile, Hennessey also offers the optional upgrade to the historic 1966 24 Hours of Daytona Ford Mark II GT40 red, white, and black livery, as seen in the vehicle in the gallery above. The option costs an additional $4,950.