Mustang muscle comes in the form of a supercharged 5.4-liter, dual overhead cam, iron-block, 32-valve V8 with Ford GT aluminum cylinder heads, piston rings and bearings. Pistons are forged aluminum and the crankshaft if forged steel. Horsepower for the 2006 Ford Mustang Shelby Cobra GT500 is rated at 450 (at least) and torque peaks at 450 lb.-ft. And since heat robs engine power, the GT500 is equipped with an upgraded cooling system and an aluminum hood with heat vents.