The Ford Shelby Mustang GT350R’s 5.2-liter naturally-aspirated V8 is perhaps one of the most evocative engines ever fitted in an American car.

Thanks to its flat-plane crank and the pony car’s special exhaust system, it emits a spine-tingling rumble unlike any other Mustang before it. The engine doesn’t just sound good, it also churns out 526 hp and 429 lb-ft (581 Nm) of torque. It’s little wonder why the GT350R shot up in value the moment it was released.

However, as incredible as the car is, Hennessey Performance thought it could make it better and swiftly developed a ‘HPE850’ upgrade package for the pony car. Filmed during a recent round of testing at the tuner’s Texas headquarters, the finished product is absolutely demonic.

The devil has risen

As you would imagine, the presence of a supercharger changes how the vehicle sounds. The noises produced from the engine bay are no longer restricted to the devilish growl of the 5.2-liter V8 and now include the characteristic scream of a supercharger. If you like the sound of supercharged V8s, we can’t imagine any better than this.

As the name of the upgrade package suggests, it increases power in a huge way and during recent dyno test runs, Hennessey’s HPE850 GT350Rs have consistently put down up to 790 hp at the rear wheels. This added grunt means the car can reach 60 mph (96 km/h) in a rapid 3.3 seconds and allows for a quarter mile run of just 10.8 seconds at 133 mph (214 km/h).

If we were fortunate enough to own a GT350R, we’d probably leave it bone stock. However, if you own one and are yearning for a little more power, this is one solution to consider.