1966 Shelby 427 Cobra
1966 Shelby 427 Cobra. Click image to enlarge

Story and photo by Bill Vance

The A.C. Cobra, also called the Shelby-A.C. Cobra, or Shelby Cobra, was an example of the practice of stuffing big American engines into light English roadsters, an idea that spawned such cars as the Railton-Hudsons of the thirties, and Cadillac-Allards and Nash-Healeys of the fifties. But in the Ford-engined A.C. Cobra, the genre was pushed to previously unheard of performance horizons; the A.C. Cobra’s acceleration was second to none among the world’s production sports cars.

The A.C. side of the marriage dated back to 1900 when John Portwine, a prosperous London butcher, decided to enter the emerging motor age. Needing expertise he teamed up with John Weller, a talented engineer.

Weller’s first prototype car, displayed at the 1903 Crystal Palace Motor Show, was a design of merit, but beyond the resources of the young enterprise. Instead, they started with a light, inexpensive commercial delivery van.

The Auto Carrier as they called it emerged in 1904 as a small three-wheeled machine powered by a one cylinder air-cooled engine with chain drive to its single rear wheel. The Auto Carrier proved reliable and popular, and by 1907 Portwine and Weller produced a passenger version, later called the Sociable.

Now under the name Autocarriers Ltd., (from which came the A.C. car name) the company prospered, moving in 1911 from London to Thames Ditton, Surrey. By 1913 Weller had developed a smart four wheel car but the First World War prevented its introduction until 1919. That was also the year that Weller also brought out an overhead cam, 1.5 litre (later 2.0 litres), six cylinder engine that would prove sound enough to stay in production into the 1960s!

In 1922, A.C. came under the control of an ex-race driver and pig farmer named S.F. Edge. It went into voluntary liquidation in 1929, but was bought and revived by brothers, William and Charles Hurlock. They resumed production in 1931 and built a variety of cars, except for a production hiatus during the Second World War when they did war work.

By the 1950s, A.C. was concentrating on sports cars, which, alas, were becoming obsolete. Then in 1953 the Hurlocks were introduced to a roadster designed by John Tojeiro, a proprietary sports car builder/engineer. Its sleek modern lines appeared Ferrari-inspired, and underneath was a ladder-type tubular frame and 4-wheel independent suspension via transverse leaf springs. It was a big improvement over A.C.’s solid axles.

The Hurlocks made a deal with Tojeiro, and his car formed the basis for the A.C. Ace, which was a hit at the 1953 London Motor Show (a coupe version, the Aceca, came a year later). It had A.C.’s venerable six cylinder engine, and was joined in 1956 by the Ace-Bristol with the Bristol six of BMW heritage. When Bristol discontinued its six in 1961, A.C. briefly used modified Ford Zephyr sixes.

At about this time several streams began converging that would lead to the A.C. Cobra. A tall Texan named Carroll Shelby, who had been forced out of race driving by a weak heart, was attempting to develop an American sports car. Upon learning that Bristol no longer built engines, Shelby approached A.C. with the idea of fitting an American V-8 in their cars.

A.C. was receptive, and agreed to send him Aces without engines. Shelby convinced the Ford Motor Co. to supply him with the light, modern, small-block overhead valve V-8 just introduced in the Ford Fairlane intermediate. An assembly plant was set up in Venice, California, and the first A.C. Cobra emerged in 1962.

The A.C.’s chassis was strengthened to take the 4.3 litre (260 cu in.) Ford V-8, the fenders were flared to accommodate wider tires, and four-wheel disc brakes were fitted. The V-8 drove the rear wheels through a Borg-Warner four-speed manual transmission and a limited-slip differential.

About 75 Cobras were built with the 4.3 engine, and then Shelby started installing the larger 4.7 (289 cu in.). He introduced the Mark II version in 1963 with rack-and-pinion steering.

In 1965 Shelby launched the Mark III with a new, stronger chassis and A-arms and coil spring suspension replacing the transverse leaf springs. In addition to the 4.7, it could also be had with Ford’s 7.0 L (427 cu in.) V-8, which turned it into a truly awesome machine. Shelby’s A.C Cobra production stopped in 1968 after more than 1,000 had been built.

As would be expected, the combination of high power and a small car with a 2,286 mm (90 in.] wheelbase, and a weight of only 916 kg (2,020 lb) produced spectacular performance. Road & Track magazine (9/62) recorded zero to 96 km/h (60 mph) acceleration of 4.2 seconds, zero to 161 (100) of 10.8, and a top speed of 246 km/h (153 mph) with the 4.3 L, 260 horsepower engine. Wheelspin would probably prevent the larger engines from accelerating appreciably quicker.

The A.C. Cobra built up an enviable competition record, becoming the scourge of Corvette and Ferrari drivers. Original A.C. Cobras made such a lasting impression on enthusiasts that they are now very valuable collectibles, and became such a favourite of replica builders that over the years an estimated 150 companies have produced A.C. Cobra replicas.

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