The Shelby GT500 is all about power. A 500-horsepower supercharged V-8 would be a lot to put in any street car. Stuffed into the body of a small-ish coupe, the Ford Mustang, it's just about over the top. For comparison purposes, the "regular" V-8 Mustang GT has a 300 horsepower engine and it is by no means underpowered.