The 2008 Ford Shelby GT500 is available as a 2-door, 4-seat coupe. Starting at $47,155, the 2008 Ford Shelby GT500 Convertible is powered by a 5.4L , 8 -cylinder engine mated to a manual transmission that returns an EPA estimated 14-mpg in the city and 20-mpg on the highway. The top of the line 2008FordShelby GT500Coupe , priced at $ 42,330 , is powered by a 5.4L , 8 - cylinder engine mated to a manual transmission that returns an EPA estimated 14-mpg in the city and 20-mpg on the highway.