In 1967 the high-end Ford Mustangs receive a 6.4-liter engine (390 CI); Always ahead for small high-performance series, Shelby releases the GT500 with a 428 CI engine. Logically, it is Shelby that Goodyear addresses to test the endurance of its tires.
Don McCain, a former Shelby employee, suggests equipping a GT500 with a 427 CI engine. Carroll Shelby makes a car prepared as a special, nicknamed Super Snake in his brand. It travels 500 miles on the Goodyear test circuit, with an average speed of 142 mph and a top speed of 170 mph.
The tires behave very well but this spectacular demonstration is not applicable industrially : they had been inflated with nitrogen to limit the overheating.
The production yield of the 427 engine is low and the upgrading from the GT500 base model is too expensive : McCain and Shelby wisely give up on a series of 50 that would have been the fastest road-legal cars of that time. The prototype is sold and has no continuation for half a century.
Both are now deceased. They had never forgotten the exceptional speed of this car in its single test and had signed together several identification plaques in anticipation of a series of replicas. In May 2018 Shelby American announces a limited edition of ten GT500 Super Snakes built on 1967 Mustangs equipped with a 427 CI slightly more powerful than the vintage engine.
The 1967 GT500 Super Snake was sold for $ 1.3M before fees by Mecum on May 17, 2013. The auction house had shared a video on YouTube. This car is now estimated $ 1M for sale by Mecum in Kissimmee on January. 11, lot F 124.