It was determined that he would need a heart transplant, and although his illness dept him from being involved in the Viper project in a hands-on way, he still provided input on the project. After his transplant, he even drove a Viper at the Indy 500, at the age of 68.
In the earliest years of the new millennium, Shelby and Ford came together again, and he consulted on the designs for the newest Ford GT. During this period, he took Shelby American public, and Caroll Shelby International and Shelby Automobiles. The latter company spun off an auto parts company, which produced parts for the Shelby Mustang.
Various other auto-related companies followed. By the time he was in his late ‘80s, declining health forced him to become much less active in both his production companies and his roles consulting and advising, but his interest in high-performance vehicles never waned.
He finally passed away on May 10, 2012, not long after the fiftieth anniversary of the original Cobra, having left an indelible mark on the world of cars and racing.