SVT isn’t trying to top its supercharged GT500 engine here. Instead, expect a version of the 5.0-liter V-8 that powers the Mustang GT. This engine might have a slightly larger displacement than the stock unit, and SVT is known to be working on a flat-plane crankshaft for the “Voodoo” engine. The lower rotating mass with such a setup should allow this V-8 to rev past 8000 rpm and deliver about 550 horsepower. We expect this engine to be mounted exclusively to a manual transmission and send its power through a limited-slip differential.
Figure about $50,000 for this 2016 model.
Via: http://www.caranddriver.com/features/2016-ford-mustang-shelby-gt350-feature