Both Ford and Carroll Shelby recently brought back the a new version of the very fast Shelby GT-500 Mustang in 2007. Mr. Shelby helped create the special Shelby GT-350 and GT-500 versions of the Mustang beginning in 1965. The 2007 Shelby GT500 had a 5.4-liter V8, which produced 500 hp. In 2008 a KR version with 540 hp was added.