Shelby dropped a 289 high-performance Ford motor into a lightweight English AC Ace chassis and went racing. This plucky little sportscar called the Cobra turned into a Ferrari and Corvette killer. The more powerful but less successful 427 Cobra was next. For endurance racing, Shelby developed the Cobra Daytona Coupe. Then Henry Ford II called, and Shelby stepped up to work on the Ford GT40 Mark II and Mark IV.