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.