Production of the all-new 2015 Ford Mustang is now underway. But for some that's not enough. They want the high-performance Mustang GT350 in their garage. All in good time, as the Shelby GT500 successor is expected to debut at Detroit in January. For now we'll have to settle for leaked details, more of which we're able to bring you today. Although official horsepower and torque figures are still unknown, a newly leaked document reveals the car's engine: a naturally aspirated 5.2-liter V8.

Previous rumors claimed the Mustang GT's 5.0-liter V8 would be given some extra power, but Ford has apparently gone a step further here. Just to give you an idea as to how powerful the 5.2 unit will be, the 5.0-liter V8 produces 435 horsepower and 400 lb-ft of torque. The GT350 obviously won't be a direct competitor to the Dodge Challenger SRT Hellcat and its 707-hp unit, but this new high-performance Mustang will still cause plenty of mayhem.