Ford has launched a new Mustang race engine, albeit for a spec North American race series. Sanctioned by IMSA and comprising ten races over five events next year this series will cater for the Ford Mustang Dark Horse R, a model that will be provided by Ford Performance as a turnkey racecar. Those cars must not be modified by competitors.

The Mustang Dark Horse road car was revealed last year as a high performance version the latest, seventh-generation Mustang. It is available in road guise and as a track-only Dark Horse S version and as the race-orientated Dark Horse R. Compared to the S, the Dark Horse R has certain race-specific items such as a competition-spec fuel cell, upgraded suspension components and so forth.

The R shares several components with the road-going Dark Horse including its naturally aspirated 5.0 litre V8, its Tremec 3160 manual transmission and Torsen limited slip differential with 3.73 final drive ratio. The engine is the latest fourth-generation Coyote V8, which features internal revisions and introduces dual air intakes and dual throttle bodies.

All of the Dark Horse Mustangs use a modified version of this V8 having a unique crankshaft and forged pistons and con rods from the sixth-generation Shelby GT500. The compression ratio is 12:1 and the output in road trim is quoted as 500 bhp at 7250 rpm with maximum torque of 567 Nm at 4900 rpm. Compared to the road car the R drivetrain features an upgraded oil system, a Ford Performance oil pan, upgraded differential cooling and a Borla race exhaust.

The R is the third Dark Horse-based racecar to be unveiled by Ford this summer, following the Mustang GT3 and Mustang GT4. Ford reports that the R, like the S version will have a similar, circa 500 bhp output to the road going Dark Horse. This means that the Dark Horse R will be just a little slower than the new Mustang GT4, which exploits around 500 bhp under class Balance of Performance. Compared to the GT4 the R will be slightly heavier and it will have slightly less downforce.