In 1965, Ford was looking for a performance version of the Mustang and wanted a two-seat car to compete with the Chevy Corvette. In partnering with Shelby-American it was able to accomplish both goals. Shelby-American took a Mustang 2+2 fastback, removed the back seat, and modified the stock 289-cid V8. The 289 motors were used because Ford’s big block V8 engines would not fit into the Mustang’s engine bay. Plus, the small block motors worked best for road racing.