Hennessey's HPE850 upgrade package for the GT350 & GT350R sounds incredible, but listen carefully: it moves by fast.

Ford's Shelby GT350 Mustang is already a legendary piece of machinery, with its incredible performance matched only by the ear-splittingly awesome sound of its 5.2 liter Voodoo V8, thanks in no small part to its exotic flat-plane crankshaft. However, for some people, stock will never be good enough, no matter how potent the car is straight off the showroom floor.

We salute you, because your demand has resulted in what may be the most impressive GT350 to date, the Hennessey HPE850. In case you haven't guessed, that number refers to the horsepower at the crank, thanks to the addition of a positive-displacement, 2.9 liter supercharger pushing 5-6 pounds of boost.

Hennessey's website shows full specifications for the car, including a dyno run showing nearly 790 horsepower to the rear wheels. That's a Demon hunter if we ever saw one, with an excellent chassis to match. It's an appropriate comparison – after Hennessey's modifications, the HPE850 GT350R sounds like the devil himself.

There's more to the package than just the supercharger, though. Hennessey upgrades the induction and the exhaust system to help the engine breathe, and installs a modified fuel system to feed the beast. Each Hennessey HPE850 GT350 is tuned, serialized, and warrantied for two years or 24,000 miles.

The end result is a 0-60 time of just 3.3 seconds, with the quarter mile coming in just 10.8 seconds at 133 miles per hour. That's some serious, peel-your-eyeballs-off-the-back-window performance. To be able to buy a ten-second hot rod as a complete, professionally-built package is mind-blowing, and the fact that it comes with a warranty is even more impressive. Naturally, no price is listed on the Hennessey website, but like our dads always said: "If you have to ask..."

Source: Hennessey Performance on YouTube