Video: Hennessey's Venom 1000 Is Probably the World's Fastest Ford Mustang Shelby GT500. Not long before the Winter Holidays, Hennessey strapped a Christmas tree to the roof of their Venom 1000 Ford Mustang Shelby GT500, put the 'Grinch' behind the wheel, and recorded a 192 mph (309 kph) top speed run.