Autoblog and Yahoo may earn commission from links in this article.The 2013 Shelby GT500 was the last and most powerful S197 Mustang, built on the 5.8-liter Trinity V8. This example has been transformed into a dyno-proven 834-wheel-horsepower monster with a wide-body kit and the desirable six-speed manual. It sits on Cars and Bids at $20,500 with six days to go.2013 Ford Mustang Shelby GT500Cars & BidsWhat it's worth right nowClean, stock GT500s have appreciated as the last of the S197 Shelbys, though heavily modified cars occupy a different market. According to Kelley Blue Book and current listings, clean, low-mileage stock GT500 coupes generally trade from close to $45,000 into the mid $60,000s, while an extensively modified, wide-body example like this one trades differently, since the modifications narrow the buyer pool.AdvertisementAdvertisementFair value for a heavily modified example like this sits close to $30,000 to $50,000, most likely close to $36,000 to $44,000, with the quality build and low mileage supporting the figure and the notes below tempering it. At $20,500 with six days remaining and a reserve, the bidding should climb into that range.2013 Ford Mustang Shelby GT500Cars & BidsCondition and detailsThe car is a serious, high-power build, so it should be valued on the finished product. Finished in black with blue stripes, it runs the 5.8-liter supercharged Trinity V8, now fitted with a Whipple Gen 5 supercharger, Injector Dynamics injectors, a dual fuel-pump system, headers, a revised tune, and a McLeod clutch, dyno-verified at 834 horsepower and 906 lb-ft at the wheels, through the six-speed manual.2013 Ford Mustang Shelby GT500Cars & BidsIt also wears BC Forged wheels, H&R coilovers, and a Wilwood big brake kit, and it shows just 5,800 miles. Several points deserve attention. The car wears a custom wide-body kit with extensive Shelby carbon-fiber panels, and various panels were repainted during the install, so it trades differently from a stock, preservation-grade car, since many GT500 buyers prize unmodified originals.2013 Ford Mustang Shelby GT500Cars & BidsThe modifications may affect emissions in some states, so confirm registration. Crucially, the tires carry 2019, 2020, and 2021 date codes, which is dangerously old for an 834-horsepower car, so budget to replace them immediately. Modifications rarely recoup their full cost, so price it as the build it is.2013 Ford Mustang Shelby GT500Cars & BidsAdvertisementAdvertisementThe offerSpecificationDetailMakeFordModelMustang Shelby GT500Year2013Mileage5,800 milesEngine5.8-liter supercharged V8Power834 hp and 906 lb.ft of torque at the wheels, dyno-verifiedTransmission6-speed manualDrive typeRear-wheel driveExterior colorBlackInterior colorCharcoal Black and blueCurrent bid$20,500, with six days leftInterested in this 2013 Ford Mustang Shelby GT500 Coupe? View the listing here.What makes the GT500 uniqueThe 2013 Shelby GT500 was a genuine milestone, the most powerful factory Mustang of its era and the first to break the 200-mph barrier. At its heart sat the 5.8-liter, 32-valve Trinity V8, a supercharged monster that produced 662 horsepower from the factory, making it one of the most potent muscle cars ever built at the time. Ford backed that engine with meaningful chassis upgrades and styling revisions, creating a car that could genuinely challenge exotic machinery in a straight line while remaining a usable, characterful Mustang.2013 Ford Mustang Shelby GT500Cars & BidsThat already-mighty foundation is exactly why the Trinity-powered GT500 became such a popular tuning platform, since the engine responds so well to more boost and supporting modifications. This example takes that potential to its conclusion, with a Whipple supercharger build pushing output to a dyno-proven 834 wheel horsepower, backed by upgraded fueling, braking, and suspension, and wrapped in an aggressive wide-body. For a buyer who wants staggering, tire-shredding performance and the involvement of a manual gearbox, a build like this delivers enormous capability.My takeThis is a car for a specific buyer, one who wants a genuinely fast, seriously built GT500 rather than a stock collector piece. The build is comprehensive and, crucially, dyno-verified, so the 834-wheel-horsepower figure is real, and the supporting braking, suspension, and fueling upgrades suggest it was built properly rather than just for headline numbers. The wide-body is polarizing, which is the main reason it trades below a pristine stock car.AdvertisementAdvertisementFair value sits close to $30,000 to $50,000, most likely close to $36,000 to $44,000, reflecting the quality build and low mileage against the wide-body and heavy modifications. Before bidding, get a thorough inspection of the build and drivetrain, replace the dangerously old tires immediately, and confirm the emissions situation where the buyer lives. Handle that, and this is a monstrous amount of performance for the money.Disclaimer: This post is for informational purposes only. We are not a dealership or broker. All vehicle specifications, pricing, and availability are subject to change without notice. We are not responsible for typographical errors, omissions, or the accuracy of the provided information. Please verify all details directly with the seller.Autoblog aims to feature only the best products and services. If you buy something via one of our links, we may earn a commission.This story was originally published by Autoblog on Sep 4, 2026, where it first appeared in the Car Buying section. Add Autoblog as a Preferred Source by clicking here.