When it comes to sleepers, this inconspicuous Ford Transit van tops the list. Powered by a 3.5-liter, twin-turbocharged V6 from Jaguar Sport, the 540 horsepower available ought to provide more than enough to leave cocky Ferrari owners with their jaws dropped when it blitzes them between stoplights.

It’s more than just an unsuspecting dragster, too. This particular Transit was used as a test bed to help develop Jaguar’s XJ220 back in the late 1980s, and as such, received the brakes and the suspension from the swoopy hypercar. Therefore, it’s capable of holding its own on the track, as our man Justin Law is happy to demonstrate.

Back in the late ’80s, the Benetton Formula 1 team used Ford DFR engines, and were given access to the pre-production Transit vans to move parts and personnel. As it happened, this van was eventually parked in the garage of a certain Tom Walkinshaw, who was closely affiliated with Benetton at the time, and several years later, he needed something to begin developing the then-new Jaguar XJ220’s engine. Using the dusty Transit van collecting cobwebs in the corner of his garage, he mounted the motor just ahead of the rear axle and began his work.

Aside from the XJ220 wheels, there’s nothing giving away what’s under the skin. Photo credit: motorsportretro.com

Since the swapped van initially used the standard Transit suspension, wheels, and brakes, it plowed horribly any time he touched the throttle mid-corner. When Justin Law bought the van years later, he modified it with an XJ220’s hubs, brakes, and heavily-cambered tires in an effort to rid the sleeper of its terminal understeer, harness the incredible thrust of the motor, and offer some mid-corner confidence. Penske shocks up front and Ohlins in the rear allow for a little more body control and gives Law, winner of this year’s Goodwood hillclimb, the confidence to hustle it without fear of topping over.