• This car was used as a test bed by Ford and several aftermarket partners.
  • A custom ECU and other upgrades allow the GT’s supercharged V8 to deliver 633 hp and 549 lb-ft.
  • Both the exterior and interior are just like any regular production model.

The Ford GT is among the greatest American supercars ever created, and one important prototype is heading to auction on September 7.

This GT is said to be one of just two units built after Ford started producing customer cars. It served as a testing and validation tool for the brand, as well as SVT, Ford Racing, and several aftermarket specialists. The whereabouts of the second test vehicle aren’t known but Mecum says this is the only one in circulation.

Read: 2006 Ford GT Owner Suing Dealer For Not Disclosing Prior Crash May Have Been Involved In Another Viral Crash

Like the production-spec car, a 5.4-liter supercharged V8 drives the mid-engined beast. However, this prototype has a bespoke ECU tuned by Ford Powertrain Engineering and on a dyno, delivered 633 hp and 549 lb-ft (744 Nm) of torque at the wheels back in the day. That’s significantly more than the 550 hp and 500 lb-ft (678 Nm) of cars delivered to customers, and those numbers were quoted at the engine, not the wheels.

Several other upgrades have been made. For starters, there’s an under-drive supercharger pulley from Steeda Autosports, an ARP half-shaft bolt and washer kit, Borla long-tube headers, and a Ford Performance muffler. Making the car even more desirable is the fact that unlike so many other manufacturer prototypes and test vehicles, the exterior and interior are identical to the production car.

 This 2006 Ford GT Prototype Helped Create A Legend

Ford painted the car in a lovely shade of Tungsten alongside silver racing stripes. It continues to sit on the original wheels and sports red brake calipers. Inside the cabin, there is black leather upholstery and an updated Pioneer head unit with Bluetooth.

Mecum hasn’t said how many miles the GT has under its belt nor how much it expects it to sell for. However, if you’re interested, be sure to check out the online listing.