AC, an English company, started building the Ace in 1953 with the Bristol 6 cyl engine, when production of this engine ceased in 1961, they used the 2600cc Ford Zephyr engine but with alloy head and triple weber carbs, proving unreliable. Shelby America took the antiquated AC Ace chassis from England, inserted a small block Ford V8 and reengineered the car to handle. They took the car to the world championship sports car racing and beat all rival brands including the existing champion, Ferrari. So the first AC Cobra, the Mk I, had the 260 cu in Ford V8, 75 were made and in 1963 a further 51 were built with the 289 The 1963-65 Mk II got rack and pinion steering, and the 289 V8, 528 were made To become more competitive with the Corvette, the 1965-67 Mk III got the big block 427 cu in Ford V8, a new chassis, coil suspension all round, wider fenders and wider radiator opening. 300 were made with the 427 (27 narrow fender 289s were also built) To celebrate 50 years of the 427 Shelby Cobra, 50 of these anniversary models were built, complete with CSX serial numbers (CSX4550-CSX4599) Available in the $120,000 fibregalss body or $180,000 polished aluminium body.