Classic Cars Wiki
Classic Cars Wiki
National Car show 114

Shelby Cobra

The Shelby Cobra was an Anglo-American sports car produced by a collaboration between American automobile manufacturer Shelby and British manufacturer AC Cars.

Overview and Development[]

Since late '62 when the new GM Stingray was shown up briefly by the Mk1 Cobra (until hub failure intervened) the development of the Grand Sport Corvette program had continued at a pace and was thought to be going for a build series of 125 cars. This would allow GM to compete directly in the FIA GT class of racing. Just to compound this Enzo Ferrari was trying to pull another "fast one" on the FIA with the request for the homologation of the 250LM. The FIA had not forgotten the serious lack of production of the 250GTO, which it had granted homologation in advance of Enzo's assured 100 minimum per year... Just thirty six were produced over three years with two very different chassis. Neither of which were too similar to the 250 GT which was supposed to form the basis of the vehicle. In an effort to prepare for the task ahead alternative engines were considered. Whilst the 289CID leaf-spring Cobra was totally dominant is the US domestic race series (USRRC), with only one race lost in three years of racing, the situation in the FIA GT class was different. This was mainly due to the number of circuits which allowed for much higher sustained speeds. Here aerodynamics took a greater hand and put the roadster at a disadvantage. This was offset by no less than AC, Shelby and the Willment team building their coupes.

Shelby had earlier in '64 fit a larger Ford FE engine of 390 cubic inches (6.4 L) in to CSX2196. Unfortunately the car was not able to receive the development it needed as resources were aimed at taking the crown from Ferrari in the GT class. Ken Miles drove and raced the FE-powered Mark II at Sebring and pronounced the car was virtually undrivable, naming it "The Turd" It failed to finish with the engine expiring due to damper failure. A new chassis was required developed and designated Mark III. CSX2196 was revised for the show down at Nassau which allowed a more relaxed class division of racing. This allowed the GT cobras to run with prototype Ford GT, GM Grand Sport Corvettes and Lola Mk6. The first meeting that the GS Corvettes turned up to in '63 it was clear that they were going to be difficult for the Cobras to beat with out development / evolution. It was for this event in '64 that the Fliptop cobra was used. The aluminium 390cid engine was used from the Sebring outing. After the first lap this rocket had pulled out a lead of almost the length of the start finish straight on the GS Corvettes ! It was not to last though as the car failed to finish.

The new car was designed in cooperation with Ford in Detroit. A new chassis was built using 4 in (102 mm) main chassis tubes (up from 3 in (76 mm)) and coil spring suspension all around. The new car also had wide fenders and a larger radiator opening. It was powered by the "side oiler" Ford 427 engine (7.0 L) rated at 425 bhp (317 kW), which provided a top speed of 164 mph (262 km/h) in the standard model and 485 bhp (362 kW) with a top speed of 185 mph (298 km/h) in the competition model. Cobra Mark III production began on the 1st of January 1965; two prototypes had been sent to the United States in October 1964. Cars were sent to the US as unpainted rolling chassis, and they were finished in Shelby's workshop. Although an impressive automobile, the car was a financial failure and did not sell well. In fact to save cost, most AC Cobra 427s were actually fitted with Ford's 428 cubic inches (7.01 L) engine, a long stroke, smaller bore, lower cost engine, intended for road use rather than racing. It seems that a total of 300 Mark III cars were sent to Shelby in the USA during the years 1965 and 1966, including the competition version. 27 small block narrow fender versions, which were referred to as the AC 289, were sold in Europe. Unfortunately, The MK III missed homologation for the 1965 racing season and was not raced by the Shelby team. However, it was raced successfully by many privateers and went on to win races all the way into the 70s. The remaining 31 unsold examples were detuned and fitted with wind screens for street use. Called S/C for semi-competition, an original example can currently sell for 1.5 million USD, making it one of the most valuable Cobra variants.


The Shelby Cobra ran on a Ford 260 in (4.2 L engine) which was a lightweight small block V8 engine.


v · d · e
Shelby vehicles