Carroll Shelby tuned first-generation Mustangs from 1965 to 1970. One of the Shelby-tuned Mustangs was the Shelby GT500. He claims that the Mustangs after 1970 were too heavy. In 2006, Shelby started tuning Mustangs again and brought back the Shelby GT500 Mustang.I frequently see the Shelby GT500 on the Houston roads as well as at Houston Cars and Coffee events. It looks just like a regular