While racing in Europe and North and South America throughout the 1950s, Caroll Shelby cherished one dream; building the world's fastest sportscar. By 1956 he had already come up with a name for his car, it would be named Cobra. Soon after his 1959 24 Hours of Le Mans victory for Aston Martin, Shelby was struck by heart problems. Reluctant to do so, he was forced to give up motor racing as a driver. This did give him time to make his dream come true.
Early in the 1950s John Tojeiro designed small sportscar, which was sold under the AC Ace name. Installed in the simple but effective tubular chassis was the Bristol 2 litre six cylinder engine. This unit was derived from BMW's 328 engine and its design dates back to 1919. Its lightweight chassis and body, and effective engine made the Ace a moderately successful racer. When Bristol announced that the 2 litre engine would be phased out, AC was left without an engine to power the Ace. Previous attempts to install other engines, like American V8s had failed miserably and the end of the Ace production was announced.
When Shelby read about the end of the AC Ace, he immediatly contacted AC and his long time associates Ford. He convinced AC to continue constructing the Ace and Ford to supply special versions of their Fairlane engine for installation in the AC chassis. Shelby flew over to the UK to supervise the construction of the prototype chassis, which featured modifications designed by Shelby to ensure the hybrid would be driveable.
Although the displacement of the Ford '260' V8 was more than twice as large and the initial 260 bhp output almost twice as large as the Bristol's, the Ford unit weighed less. Main diffuculty in incorporating American V8 engines was their rather high torque figures. The rear-end needed considerable modifications to handle the torque produced by the Ford. With the beefed up rear suspension, the AC chassis took to the Ford V8 engine surprisingly well and after extensive tests 100 chassis/bodies and Ford V8s were ordered. Shelby's Cobra was born!
The V8 Ford engines were derived from the ones used in the Fairlane and Fairlane 500, but they were delivered to Shelby in a somewhat 'tweaked' form. Breathing through a single Holley Carburetor and fitted with 'hotter' cams, solid tappets and larger ports, the V8 was good for around 260bhp. For competition use Shelby modified the engine even further. With an increased compression ratio and breathing through four twin-choke Webers figures of 335 bhp could be achieved, with the engine revving up to 9000 rpm. Stunning performance was the result of this very powerful engine, which is reflected by the acceleration and top speed figures. Had Shelby succeeded in building the world's fastest sportscar?
In the mean time, the world's largest manufacturer and Ford's biggest competitor, General Motors worked intensively on building their fastest GT-racer yet. Dubbed Sting Ray, the fastest Corvette to date was set to make its debut at the 1962 Riverside 3-hour race for Grand-Touring cars. Coincedently Shelby's workshop was around the corner of the Riverside track and his competition Cobras were about ready to make their debut as well. So in a weird twist of fate, both GM's and Ford's latest racers made their debut in the same race. In qualifying Shelby took the wheel of one of the two Cobras entered and shocked the crowd and even more so GM's racing division by lapping over four seconds faster than the fastest Sting Ray. In the race Bill Krause (pictured above) had built up a lead of over 30 seconds in the first 30 minutes. He was forced to retire when a wheel came off and in doing so he handed the victory to one of the Sting Rays. A legend was born that day, but it wasn't the Sting Ray!
Vowing to decimate the Sting Rays in the following season, Shelby and his Cobras took part in the first US manufacturers' championship. The Cobra's dominance was total and Shelby took the title with 111 points over Ferrari's 28 and Chevrolet's 19. All but one of the seven races of the championship were won by a Cobra. After this big US success, Shelby set out to take on Ferrari in Europe with more powerful and coupe bodied versions of the Cobra. He succeeded and scored class victories at Le Mans and in 1965 the World GT Championship was his, a mere three years after the Cobra's birth.
Caroll Shelby decided to up the ante once more by installing the 7 litre V8 that had powered the GT40 to the Le Mans win in the Cobra chassis. The added power and weight required some serious modification ranging from increased tubes for the frame and fully independent suspension at the back. To get the power on the road wider tyres were also fitted, which required bigger wheelarches, considerably increasing the width. The most potent version of the 427 engine available for competition use produced in the region of 550 bhp.
Although the FIA was lenient with homologation in the past, they had become very strict after Ferrari tried to get the 250 LM homologated and told Shelby at least 100 Cobra 427s built within a year were required to pass the homologation. Unfortunately when the FIA dropped by the workshop, there were only 53 examples completed and the homologation was refused. Of the 53 just 16 were already sold to customers in full competition spec. Three more cars of the same spec were retained by the factory and the remaing 34 were sold to the public as S/C or Semi Competition model ford road use. In the following years another 250 seven litre Cobras were produced, but it was too late for homologation.
Featured is CSX 3017; a highly original example of the 16 competition 427 Cobras sold. It was successfully campaigned in the 1966 by the Ford of Canada works driver George Eaton. Despite being only twenty years old he coped with the 550 bhp remarkably well, winning his class in all eighteen regional and national races he competed in. In a 6 Hours race at Mosport he even beat his team's Ford GT40. It has since survived virtually undamaged with the original and body still fitted. Painted in familiar Cobra colours, the very rare 427 Cobra is seen in action here at the 2006 Monterey Historic Races.
There is so much mis-information on these cars it is difficult to know where to start, but how about weight and horsepower. 550 horse power with 472 Ft/Lb at 3700 rpm get real. You would need 472 lb/ft at 6100 rpm to make 550 horse power. The Cobra race cars "back in the day" were lucky if they made 480 horsepower, this can be proven by reviewing data from Ford Motor Company dynamometer records from that time period. The dual 4-barrel engines were in the low 500 horsepower range with the single fours slightly lower in power.
Weight, comp 427 cars weighed on the order of 2350 lbs not 2150 pounds. All Cobra's 289's and 427's did not handle, they had abysmal suspension geometry with roll centers higher in the front than the rear on 427 models and reverse Ackerman on 427's because of wheel clearance issues. They had very low torsional rigidity and no camber gain which contributed to their poor handling. The only reason they won races was their excellent power to weight ratio (for the time) which provided superior acceleration and deceleration.
These cars have been romanticized by the legion of kit car owners
wishing they were better than they were so that some of the glory would rub off on their replicas. A stock Corvette Z06 would eat a full race, period correct 427 Comp Cobra any day on any race track, if you don't believe me look at historic race lap times and compare. Just for the record, I own a 427 Cobra and would not trade it for any other car, but it facts are facts.
Cobras are good.
FREDZY 29-3-2003
"The Cobra is a legend because: It was a dominant force in racing in its day, was a fast, attractive car and there were few of them built. The Cobra is not a legend because: of its ""numbers"" or abilities compared to modern day cars. Watching people compare a Cobra to a ""modern day exotic"" really looks childish. There is no place to begin when trying to explain how a Cobra differs from say an F355. One can say, ""a Cobra turns good"" and apperantly as someone ranted, it also goes and stops good. Fortunately for Cobra, the old men who spill their fat wallets filled by the lower class could care less if the car could do anything better than his sons pretty Ferrari. Anyhow, if one was to compare a Cobra to anything, (and I feel that comparing car performance any way other than FOR REAL like ON A TRACK is a foolish waste of time, and goes along nicely with the saying actions speak louder than words) they should compare it to a car of its time and caliber."
Tell me this much.
fmboss429 25-1-2003
Tell me one thing. If the now so wonderful excotics market produces such incredable machines, why are they still trying to meet or beat the numbers a cobra posted so many years ago? i'll tell you why, because the cobra is the ultimate car. Any car nut will tell you they one day dream of owning a 1965 Cobra 427 s/c! Go to any classic car auction and one of the top five highest selling cars will be a Cobra. This proves that these cars are so well built and out perform modern day cars, that they are highly sought after. any man would be proud to add a cobra to their stables! so tell me why i should believe there to be a more well rounded cars then the Cobra.