Last revised: 26-1-2009

contact the RitzSite Webmaster

AC Shelby Cobra, 1962-1965: American iron Mark I & II

1964_AC_Cobra_289_Mk_II_blackAt the end of 1962 it became clear that the Cobra still had some teething problems. Next to overheating there were complaints about lack of precision in the steering and even steering failures, a weak front suspension and less performance than advertised. That last problem was taken care of by introducing a 289 ci (4735 cc) version of the Ford Fairlane engine, which also included a new radiator, in the Cobra early in 1963. This engine produced 271 hp and 426 Nm torque and gave the car a performance closer to that of Shelby's original 260 ci High-Power test car, though it came still a few horsepower short. In the months that followed the inaccurate worm and sector steering was replaced by a modern rack and pinion steering system, the front suspension wishbones were strengthened, a wider grill and side vents were added to the body to solve the overheating problems and also the bootlid was shortened for more body rigidity and the flares at the wheel arches enlarged to fit wider tires. Other changes were improved electrics including an alternator, and a longer final drive (3.77:1 instead of 3.54:1) to reduce the 0-60 mph acceleration time.

1964_AC_Cobra_289_Mk_II_Ford_engineSometime in 1963 the improvements amounted to so much that the Cobra was a distinctly better car than before, and so it was referred to as the Mk II. Question is, when exactly did it become a Mk II? Was it when the 260 ci block was replaced by the 289 ci block after 75 Cobras had been completed in the first months of 1963 or was it when the Cobra had completed its first evolution after 125 were manufactured in June 1963? Fact is that starting with car number 126 the external features identified with the Mk II appeared, like the side vents. Since the distinction is a bit hazy, even more so by all the proper Mk I versions later more or less upgraded to Mk II specs, the Cobras lacking the external features of the Mk II and built between 1962 and 1963 usually are referred to as Mk I.
A "standard" Cobra 289 weighed only 984 kg and had a maximum speed of 222 kph. It accelerated from 0-60 mph (96 kph) in about 5.5 seconds and needed 1 litre of fuel every 6.5 km. To keep this little brute, it measured 3.85 x 1.55 x 1.24 m (length x width x height), on the road it had an independent front and rear suspension constructed out of lower wishbones, transverse leafspring upper links and telescopic dampers. Solid disc brakes in front and rear provided the stopping power. For those who wanted more an extensive list of performance options was available, like high compression cylinder heads, dual 4-barrel carbs (standard it had a single 4-barrel Holley) or even four 2-barrel Weber carbs.

1964_AC_Cobra_289_Mk_IIFor a racing driver as Carroll Shelby performance was of course all important. And the way to prove the Cobra's true performance was on the racing track. As soon as October 1962 the Cobra appeared on the track, and it was there to stay.
At first it showed potential in the GT-class races, mainly because it was much lighter than its (American) competitors, but was also unreliable. The first results came in January 1963 at Riverside in the US where the Cobras finished first and second, beating the Chevrolet Corvette Sting Rays by quite a margin. At international races however the Cobra roadsters were usually beaten by Ferraris 250 GT and GTO. In June 1963 Shelby and AC both entered a Cobra in the Le Mans 24 hours race and the AC entered car finished 7th overall, trailing a total of six Ferraris. It then became clear that the Cobra 289 roadster was perfect for racing on the usually short American tracks where acceleration made the difference, but lacked the necessary aerodynamics to win international races on the longer and faster circuits around the world, where top speed mattered.
Never the less the Cobra 289 won the 1963 and 1964 United States Road Racing Championship, the 1963 Bridgehampton 500 km (first international race win for the Cobra, driven by Dan Gurney) and the 1964 Sports Car Club of America Road Race of Champions, not to mention a lot of local GT races around the world. The car in this picture was produced for the Sebring 12 hours race in 1964.

1964_AC_Cobra_289_Mk_IIMeanwhile in Britain AC Cars had officially stopped the production of the Ace in October 1963 and had nothing else to sell. So late in 1963 AC started to produce the AC Cobra for Britain and Europe next to their production for Shelby. But where in the US the Cobra was a reasonably priced car, in Europe it was very expensive and took a lot more money to buy than the (more refined) Jaguar E-type for instance. Up to 1965 AC sold 61 Cobras, mostly right hand drive (like the car above).
Shelby started to develop the Mk III Cobra during 1964, but this time the changes didn't come gradually. The Mk II 289 ci Cobra was offered until late in 1965 and a total of 580 were manufactured (including the European ones and the Mk I 289 ci model), most of them in 1964. Of that total 65 were pure racing cars or prototypes.

So the Cobra didn't sell much, but publicity-wise it was a big hit, both for Ford and for Shelby. The Cobra generated a lot of attention and this started sort of a Shelby cascade: in 1963 Shelby was contacted by the British Rootes Group who wanted something similar done to their modestly powered Sunbeam Alpine, a perky 2-seater roadster, as he had done to the AC Ace. And so Shelby put the Ford 260 ci V8 that was moved out off the Cobra into the Alpine to create the Sunbeam Tiger. As opposed to the Cobra the Tiger was mass produced and therefore more affordable and sold much better. Also in 1963, after the failure to win from Ferrari in Le Mans and Ford's ill-fated bit on this Italian manufacturer, Shelby teamed up the British Lola outfit of Eric Broadley with the Ford Company to create the now famous Ford GT-40, using the 289 ci V8 to power the Mk I version. And last but not least, in August 1964 Shelby was asked by the Ford Company to develop a high performance Ford Mustang that could compete in the SCCA races. Shelby fitted the 289 ci V8 racing engine in the Mustang fastback and created the Shelby GT-350(R), the ultimate muscle car which in its street guise was far more common on the American roads than the exotic Cobra. But still, the Cobra remained one step ahead from this competition...

...continue by clicking the arrows pointing right...