**Embargoed until 12:01 a.m. EDT, Tue., Nov. 15, 2011.** 2013 Ford Shelby GT500: The New Shelby GT500 sets a performance-driven design standard with new downforce-generating front grilles, aggressive splitter, new quad exhaust system and two new forged-aluminum wheels. Also new for 2013 is a 5.8-liter supercharged V8 engine producing 650 horsepower and 600 lb.-ft toque.