The car Rally Vincent drives is a variant of the 1967 Ford Mustang fastback, designed in co-operation with former race car driver Caroll Shelby (January 11, 1923-May 10, 2012), and was made in limited quantities during its 1967 production run.
Rally's Shelby is painted Acapulco Blue with white Le Mans stripes, and has the standard black interior. The car also features a custom taillight cluster different from the standard Mustang taillights. The G.T. 500 differs from the lighter G.T. 350 in that the G.T. 500 comes with a big block 428 V-8 Police Interceptor, mated to a Ford Top-Loader 4-speed manual. The G.T. 500 was originally rated at 355 HP from the factory, but since many American car manufacturers in those days were in the practice of "sandbagging" their numbers, the 428 actually produced somewhere around 400 HP. This was good for 7.2 second 0-60 times, and a quarter mile would be finished in 14.5 seconds at 101 MPH. All of this was accomplished on the skinny, primitive fiberglass-belted bias-ply tires of the day. Rally's car benefits greatly from modern steel-belted radial tires, usually mounted on the optional Mag-Star wheels for 1967. She has also upgraded the clutch, substituting the stiff mechanical linkage with an easier hydraulic clutch to make city driving easier.
Rally's G.T. 500 is damaged and nearly totaled several times during the course of the manga, being repaired after every incident at great expense. It eventually meets its end after being booby trapped with a bomb, which forced Rally to drive the car at high speed into an abandoned construction site. Afterwards, Rally then drove a Ford Mustang II Cobra. In the anime, it is lightly damaged during the chase with Radinov, the fiberglass hood later sporting one of Radinov's ballistic knives as a warning to Rally.
A similar car was driven by Lt. Percy in the Riding Bean OVA. The only difference between Percy's and Rally's G.T. 500s was that Percy's had yellow driving lights as opposed to Rally's plain white glass. Percy's G.T. 500 is wrecked during the events of Riding Bean, but we'll never know if he would restore the car to pursue Bean again, or buy another car instead. Percy's G.T. 500 managed to go toe-to-toe with The Buff during a high speed pursuit, but was rammed into a parked car by Bean after Percy enraged him.
In both the anime and manga, Rally refers to her car as a "Cobra" far more often than "G.T. 500". While the word "Cobra" appears on numerous places on the car, and even features multiple cobra badges throughout, the car isn't officially called a "Cobra". At the time, Shelby was most famous for producing his exotic, Ford-powered Cobra roadster (which is coincidentally what Riff-Raff is first seen driving), so Ford and Shelby decided to use the Cobra imagery to make the Shelby Mustangs even more appealing. The car is officially known as a "1967 Shelby G.T. 500". Ironically, the 1968 G.T. 500 and G.T. 500KR (King of the Road) would include the word "Cobra" in its official title.
When asked by his "assistant", Dick, if his car was a Mustang, Percy bursts into laughter and immediately corrects him, declaring that "it's a Cobra! A Shelby Cobra G.T. 500!". Percy then launches into a tirade about how his G.T. 500 will run the Road Buster off the road.
When asked why he chose the '67 G.T. 500 above any other car, Sonoda claimed he picked it because it had the most impressive stats, and because it was rare.