It's finally been confirmed that the 2020 Shelby Mustang GT500 will make its debut at the 2019 Detroit Auto Show in January. In the same month, a very special example of the original GT500 is heading to auction. What makes it so special? It's the one and only GT500 Super Snake in the world. Yes, Shelby is producing ten continuation examples of the Super Snake, but this is the only all-original example in existence.

The GT500 was a huge success, so when Carroll Shelby was approached by Goodyear to join a demonstration run to promote a new tire, the GT500 was the obvious choice. At the same time former Shelby American Sales Manager Don McCain suggested that Shelby should build a supercar using the racing 427 V8. As a result, this engine was used in the GT500 for the demonstration.

The plan was to demo the car and build a further 50 examples for the Long Beach dealer McCain was working for. The special engine was effectively a modified version of the unit found in a Ford GT40 MKII tuned to deliver 600 hp. GT500 No. 544 received the engine designed and modified to deal with extensive high-speed running, a unique transmission and bespoke rear axle. McCain described the 427 engine as 'the mother of all 427s' due to its exotic components such as aluminium heads, lightweight water pump, forged crank and Le Mans rods.

During the demonstration, Shelby took guests and journalists for a ride in the car and reportedly hit 170 mph. Goodell then drove the car for the test averaging 142 mph over 500 miles while retaining 97 percent of its original tire tread. The car was then sent to the Californian dealership to create publicity for the limited run of 50 cars. Unfortunately, as impressive as it was, the GT500 Super Snake was deemed too expensive to go into production, so the project was scrapped. The projected retail price would have been more than twice the price of a base GT500 and more than a 427 Cobra.

The Super Snake was then shipped to Dallas where it was purchased by Braniff International Airways pilots James Hadden and James Gorman, who modified the gearbox for drag racing. Eventually, the one-off Mustang was bought by a collector who lightly restored the car, and even found a new set of Goodyear Thunderbolt tires like the ones used during the test. It was then sold to its current owner, Shelby collector John Wickey. The Shelby GT500 Super Snake will be going under the hammer at Mecum Auctions Kissimmee sale on January 3 - 13 next year. Back in 2013, the one-off Super Snake sold at a previous auction for $1.3 million. At the time, that made it the most expensive Mustang ever sold, so we wouldn't be surprised if that record gets beaten.