Hennessey's 850-HP Mustang Dark Horse Is Up for No-Reserve Bid on Cars & Bids

A Vapor Blue Metallic Mustang Dark Horse carrying Hennessey's supercharged H850 package is currently up for grabs at no reserve, and the bidding is already past $46,000 with days left on the clock. The fastback, along with its full photo set and seller notes, is listed on Cars & Bids, where the auction runs through August 26.

The Dark Horse sits atop Ford's seventh-generation S650 Mustang lineup, built as the brand's answer to enthusiasts who wanted a track-focused option once the Mach 1 aged out. Factory specs already include a specially tuned 5.0-liter Coyote V8 good for 500 horsepower, plus the Dark Horse Handling Package, adjustable exhaust, and 19-inch dark-finish wheels. This example pairs the factory hardware with the 10-speed automatic rather than the Tremec manual, and according to the window sticker included in the listing, it left the factory with a $76,650 price tag before any aftermarket work.

What sets this particular car apart is the $24,950 Hennessey H850 package layered on top. The upgrade swaps in a larger supercharger system, a high-flow air induction setup, an upgraded fuel pump and injectors, and Hennessey's own HPE engine calibration to push output to a claimed 850 horsepower. Every H850 build also gets exterior badging and a serial-numbered plaque, and this car's seller added carbon fiber door sill and engine bay trim, a wickerbill rear spoiler, under-hood LED lighting with a remote control, and a Hennessey vanity plate for good measure. Cosmetic flaws are minor: some scuffing on the front splitter and a small area of removed paint near the rear Hennessey badge, which the seller says was done intentionally to prevent cracking.

With just 2,800 miles on the odometer and a clean Carfax showing no accidents, the Mustang has led a pampered life. It isn't a stranger to Cars & Bids, either: the current seller purchased this same car through the platform back in May and has only added around 800 miles since, making this something of a quick flip on a car that's barely broken in.

Stock Dark Horses are still finding their footing in the collector market. Hagerty Valuation Tools currently pegs a #3-condition (Good) 2024 Dark Horse coupe at roughly $72,600, and Hagerty's own sales data shows a wide spread for the model, from the low $40,000s for rougher or heavily optioned examples up into six figures for exceptional low-mile cars at the right auction. Modified cars like this Hennessey build add another layer of uncertainty, since Hagerty notes that aftermarket work can swing value either way depending on the quality of the build and how broadly the modifications appeal to buyers. A tuner-backed, warrantied power upgrade from a known name like Hennessey tends to hold up better than a garage-built setup, but it still won't move the needle with collectors chasing numbers-matching originality.

This isn't the first time an 800-plus-horsepower Mustang has crossed the block on Cars & Bids, either. Earlier this month a 700-mile Shelby Super Snake 60th Anniversary with 825 horsepower drew plenty of attention for similar reasons, and Hennessey itself stays busy well beyond Mustangs, most recently sending a 1,817-horsepower Venom F5 to Mecum's Monterey sale. For a deeper look at how the Dark Horse fits into the broader Mustang story, Motorious has a full rundown of the nameplate's history and current lineup.

With five days left and no reserve protecting the seller, this Hennessey-built Dark Horse is guaranteed to sell to whoever has the highest bid when the gavel falls on August 26. Anyone chasing serious power in a modern pony car without waiting on a build slot at a tuner shop should keep an eye on where this one lands.