Michael Accardi 
Ford is planning a single-make racing series based around the S650 Mustang Dark Horse, it’s believed the series could debut as early as next year. It’s unclear if the new spec series will be sanctioned by IMSA in the same vein as Porsche Carrera Cup, Ferrari Challenge, Lamborghini Super Trofeo, and Mazda MX-5 Cup, or if it will join forces with SRO and GT America similar to Toyota’s new-for-2023 GR Cup.
The plan was originally teased during the S650 Mustang’s launch last year. Ford Performance global motorsports director, Mark Rushbrook confirmed to Sportscar365 that a new Mustang-only race series is still under development. “There will be a spec series,” Rushbrook said. “We’re not sharing anything more than that yet.”
While light. on details regarding the series structure and sanctioning, Rushbook did indicate the track-only S650 Mustang Dark Horse R will act as a show pony for the series. The Dark Horse will be offered in two flavors– the Dark Horse S will be delivered as a street-legal, track-capable car, while the Dark Horse R builds on those capabilities and adds a few race-specific things like a fuel cell, roll cage, and chassis seam welds. It could also include a standalone ECU and sequential gearbox for data logging and ease of use.
Rushbrook says the Mustang Dark Horse R will take priority. “We’ll probably build more Rs than Ss at first. While we want to get them out everywhere, including racing and track days, we’re going to prioritize on getting them out racing.”
He also confirmed the Mustang Dark Horse R will show up with around 500 horsepower (courtesy of an updated 5.0L Coyote V8 engine) with the car offering peak performance just below the incoming S650 Mustang GT4, which will likely make for competitive racing. Expect the R will receive some light weighting compared to the S but don’t expect those Carbon Fiber wheels to show up for race duty.
“A Mustang Dark Horse is around 500 horsepower as a street car,” he said. “When you take that to a race car, it will still be around 500 horsepower, a little bit more. The BoP levels in GT4 are around 500 horsepower.”
“It will have similar power to a GT4 car. It will be slightly heavier and it will have slightly less aero. But it’s still going to be a quick car.”
