A remarkable piece of American muscle car history is currently up for auction on Hagerty Marketplace — a documented one-of-one 2008 Ford Mustang Shelby Turbo Prototype with just 12,700 miles on the clock.Unveiled at the 2009 SEMA Show in Las Vegas, this GT-based Shelby Turbo was a prototype post-title package developed in partnership with Turbonetics, designed to extract a hefty 550 horsepower from the 4.6L V8 found in 2005–2009 Mustang GTs. That figure eclipses even the contemporary Shelby GT500's 500 horsepower, and it was the first forced-induction package of its kind engineered to achieve full 50-state and California Air Resources Board (CARB) emissions compliance, positioning it as a viable dealer-installed alternative to Shelby's existing supercharger program.While the package never reached series production, this prototype was saved and later tested at Las Vegas Motor Speedway by Shelby American engineers and the media following its SEMA debut. Email correspondence between the selling dealer and Shelby American in 2022 confirms its one-of-one status — making it the only example of its kind in existence.The car presents Shelby American's full prototype specification. Finished in Performance White with Shelby Turbo decals over a Dark Charcoal cloth interior, it features the Turbonetics turbocharger and intercooler, Shelby Pro Plus brake system with Baer six-piston front calipers, performance suspension with caster/camber plates, Borla exhaust, short-throw shifter, 18-inch chrome-alloy wheels, a deep-draw hood with securing pins, and serialized dashboard and engine bay plaques. The factory 4.6L V8 is backed by a five-speed manual transmission and limited-slip differential, retaining the GT's original ABS and traction control systems.The selling dealer acquired the car in 2022 and has compiled an impressive documentation package, including a Ford window sticker, a Deluxe Marti Report, a Shelby Vehicle Authenticity Certificate, Shelby memorabilia, a Diablosport tuning device, and a clean CARFAX Vehicle History Report. Among the most compelling items included are photos showing the car alongside Carroll Shelby himself at the 2009 SEMA Show.With the current bid standing at $23,000 and the auction closing on Monday, June 8, 2026 at 2:00 PM EDT, this piece of Shelby American history represents a remarkable opportunity for a serious collector. A previous sale at Barrett-Jackson's Palm Beach event saw the car change hands for $70,000 — suggesting this Hagerty Marketplace auction offers compelling value for what is ultimately the only Shelby Turbo prototype ever to exist. The car is located in Covington, Louisiana and comes with a clean Louisiana title in the seller's name. See it here.⚡️ Read the full article on MotoriousSign up for the Motorious Newsletter. For the latest news, follow us on Facebook, Twitter, and Instagram.