2020 Ford Mustang Shelby GT500 reaches 708 hp on Hennessey’s dyno

Last summer, Hennessey trotted out a trio of performance packages for the 2020 Ford Mustang Shelby GT500, the most powerful street-legal Mustang Ford ever built, to give it even higher output. Now the specialty Texas shop has released a video to prove that the baseline GT500 does what it says.

We’re shown a video in which a Hennessey driver takes the factory version of the pony car around a course to put it through its paces. The conceit is that Hennessey rigorously tests every vehicle it receives before sending it to its tuners to make sure all is in good working order.

So we’re treated to the sight and incredible sounds of a GT500 riding atop a dyno. It reaches 708 horsepower at the rear wheels at around 7,300 rpm and 589.5 pound-feet of torque at 4,100 rpm on this particular dynamometer, courtesy of the factory supercharged 5.2-liter V8. Ford’s factory rating for the GT500, which is certified to SAE standards, is 760 hp and 625 lb-ft, so this specimen’s 708-hp dyno run indicates a rather small loss of power — well under 10 percent — from what the engine makes at the crankshaft versus what’s put down to the ground. That’s an impressive result.

The driver hits a speed of around 146 mph on a straight section of track, which he says is already on par with many of Hennessey’s top modified vehicles. For what it’s worth, Ford limits the GT500’s top speed to 180 mph.

The rest of the video functions largely as an advertisement for the forthcoming Venom 1000 tuning package, which will bump up output to, you guessed it, 1,000 hp, along with 850 lb-ft of torque. Hennessey also offers 850- and 1,200-horse versions of the Venom package, the latter requiring E85 or 109-octane racing gasoline.

For the Venom 1000, Hennessey upgrades parts including the intercooler, fuel delivery system, pistons and connecting rods, and a strengthened seven-speed dual-clutch transmission, the first in a Mustang. It also got a new 3.0-liter supercharger, replacing the factory 2.65-liter version, a new pulley and belt, high-flow catalytic converters and an upgraded air induction system. It will come with road testing up to 200 miles, a one-year/12,000-mile warranty and run on 93-octane fuel.

Still no word on pricing for any of the Venom packages.