John Hennessey Test Drives The Shelby GT350 HPE850 Mustang: Video

There are undoubtedly those who feel that the factory-stock Ford Shelby GT350 Mustang’s 526 horsepower simply isn’t enough, nevermind its superfluous performance on both the road and the racetrack.

For those folks, Hennessey Performance Engineering offers a couple of different solutions to boost peak engine output, like the HPE575 package that coaxes an extra 49 horsepower out of the motor using stainless long-tube headers and mid-pipe, high-flow induction system and catalytic converter, and an ECU tune. Alternatively, Hennessey offers a range of supercharger upgrade packages for the Shelby GT350 like the HPE850, which makes – you guessed it – 850 peak horsepower.

Hennessey Performance Engineering just released a video with company founder John Hennessey, wherein the former racer tries out an HPE850-equipped Shelby GT350 on the street to make sure it’s up to snuff. The car makes its power with some help from a 2.9-liter supercharger, high-flow throttle body and fuel injectors, and the same high-flow induction and exhaust bits that help the HPE575 reach its admirable figure.

In the clip, Mr. Hennessey also tosses in a quick tip regarding heel-and-toe downshifting at the 7:38 mark, in the course of talking about his experience at Ford’s Performance Racing School in Utah: “The big takeaway that [Billy Johnson] taught me was that you want to over-blip, meaning that if you’re coming to a turn and you want to downshift to third or downshift to second, when you kick your heel over to kick the gas pedal to raise the RPM up… generally, you want to just generally over-blip.”

That’s advice you can trust; Billy Johnson, remember, was one of the drivers of the No. 66 Ford GT at last year’s 24 Hours of Le Mans, and drove in a couple of other events on the 2016 World Endurance Championship calendar besides (Silverstone, Spa Francorchamps). He also won last year’s IMSA Continental Tire Championship in the Ford Shelby GT350R-C Mustang.

Catch all of John Hennessey’s thoughts on the Shelby GT350 HPE850 in the video above.