Shelby AC Cobra 427 Classic Sport Cars – Let us start by discussing the nomenclature because Shelby Cobra is often mistaken with other cars with similar names or other models with Shelby badges. One of the most common mistakes is to think of it as Ford Shelby Cobra. There is no production car with such name; it only exists today as a prototype shown at the 2004 North America International Motor Show in Detroit, Michigan. Almost all models of the real Shelby Cobra did have relation with Ford, but it was a partnership in which case Ford provided the engines and in later models helped with the design. Another one is Mustang Shelby, which actually is high performance variant of Ford Mustang; this car has several other names as well including Mustang GT500 and Ford Shelby Mustang.
Things get more confusing because Ford also uses the term “Cobra” and “Shelby” to market and sell some cars of entirely different models for example the Shelby Cobra GT350 and GT500. Neither is the car of discussion. Shelby Cobra or Shelby AC Cobra was the result of collaboration between London-based AC, Shelby American, and Ford. Eventually in 1965, AC sold the Cobra name to Ford and that was the start of all the madness in the naming creativity.
Ace Cobra or more popularly known worldwide as the Shelby Cobra was a prime example of how American and British engineering perspectives could cooperate and came up with such a timeless classic. It all started with a lesser known car called Ace made by AC (Auto Carriers) based in London.
Similar to just about every small-scale British car makers, the AC Cars used the widely popular Bristol straight-6 engines in its small volume productions including the Ace two-seater roadster. The engine was actually a derivative of the 2-liter six-cylinder BMW M328. In 1961, Bristol decided to end production of the straight-6 and replaced it with the bigger 5.1L Chrysler V8.
Because AC Cars could not get the engine it wanted, the company also made a switch; instead of using the big engine from Bristol, it opted for 2.6L V6 used in Ford Zephyr. In the same year, an American car designer Carroll Shelby contacted AC and asked if the company would be interested in building a car modified to fit with a V8 engine. AC agreed, provided that a suitable engine for the car they made could be found. Carroll Shelby then contacted both Chevrolet and Ford, and eventually the latter was willing to offer the right engine for his purpose. Ford gave Shelby brand new engine, the Windsor 3.6L small-block V8; it gave two engines in fact. From this point on, the Shelby Cobra was about to be born.
Apparently AC had already made some modifications to the Ace when they decided to switched from Bristol’s engine to the Zephyr’s. Such changes happened to also fit with small-block V8. To build the first Shelby Cobra, AC only needed to make some minor alterations by moving the steering box a little bit outward to make space for the V8 and fitting a stronger rear differential to handle bigger power. The car transformed from AC Ace 2.6 into Shelby Cobra without a lot of engineering challenges.
Prototype and Early Models
After vigorous testing and quite a lot of tinkering, the engine and transmission were removed altogether. In February 1962, or only a month after the AC Ace 3.6 prototype had been built, the engine displacement was increased to 4.3 liter. The chassis alone was then freighted to Shelby in the United States. In short, Shelby Cobra had already been a proper car in London, but then was stripped down again for re-assembly. In the hands of Shelby, the chassis was then fitted again with engine and transmission in less than 8 hours. The first 75 units of Shelby Cobra were fitted with 4.3L V8, while the remaining 51 units had bigger 4.7L V8.