AC Cobra – A Brief History

The AC Cobra, also known as the Shelby Cobra is one of the most iconic sports cars of the 60’s. The Cobra is a British sports car powered by an American engine.


In 1961, AC were approached by Carroll Shelby, who wanted them to build him a car based on the AC Ace, but one that could accommodate a V8 engine. An agreement was struck, and it fell to Shelby to find an engine. After failed attempts with Chevrolet, due to them not wanting increased competition to their Corvette, Ford provided the answer. AC developed a chassis that could accommodate the Ford 260cubic inch engine, a 4.2 Litre small block V8. Once the chassis had been sent to Shelby, his team had the engine and transmission fitted in less than 8 hours.

Just 125 Mk1 cobras were made, 50 of which had been upgraded to 4.7L engines. In late 1962, AC made some major changes to the cars front end, allowing for rack and pinion steering and leaf spring suspension. As a result it had a brief spell of superiority over General Motors Stingray. It also led to the Cobra dominating the US domestic race series. However when entered into the FIA GT class it could not maintain it’s form due to sustained high speeds being required, putting the roadster to a disadvantage.

Racing was a large influence on the development of the Cobra, always with the goal of beating the Corvette’s and Ferrari’s in the GT class. In 1964 a 6.4 Litre engine was tested in the Cobra, but had limited resources and poor development and so failed. This saw the development of a new Mk3. The new car used a new chassis, built to incorporate the infamous 427ci 7Litre engine, along with bodywork changes including wide fenders and larger radiator grille. Boasting 425bhp and a top speed of 164mph for the road version, and 485bhp with a 185mph top speed for the competition car, this is the iconic Cobra we all know and love. It may come as a surprise then that the Mk3 was a financial failure, and was never raced by a factory team. It did however compete with much success in the hands of privateers.

In the mid 1960’s, the government was becoming more and more aware of road safety and an increase in traffic accidents. It was in 1964 that an AC Cobra Coupe was calculated to have been doing 186mph on the M1 motorway. While not the direct cause of the new 70mph speed limit that followed like many believe, it went a long way to highlighting potential problems without the speed limit.