2007 FORD SHELBY GT500 OFFICIALY RATED AT 500 HORSEPOWER

The most powerful factory-built Mustang ever just got even more potent. Final certification testing of the Shelby GT500’s 5.4-liter supercharged V-8 shows it will produce 500 horsepower and 480 lb.-ft. of torque – 25 more horsepower than preliminary estimates.
“With 500 hp and the Shelby name, this car is an instant legend," said Hau Thai-Tang, director, Advanced Product Creation & SVT programs. "This is the most powerful, most capable Mustang ever."
The Ford Shelby GT500's supercharged 5.4-liter, 32-valve V-8 is a result of Ford's experience in developing the modular V-8 and V-10 engine series. The engine is force-fed air via a "Roots-type" supercharger providing 9 pounds per square inch of boost. It borrows the four-valve cylinder heads, piston rings and bearings, from the Ford GT engine.
[Source: StangsUnleashed]