The 1966 Shelby Cobra started out as a traditional style British roadster with an empty engine compartment sent by air freight from AC Motors in the U.K. to Shelby in Los Angeles in early 1962. The two seat roadster body was hand built with an aluminum body panels on a tubular steel frame. The car was fitted first with a 2.6 liter engine from a Ford Zephyr complete with transmission in eight hours. The job wasn’t finished; the front end had to be re-engineered to accommodate the weight as well as installing a Salisbury 4HU differential – the same as an “E” type Jaguars to accommodate the increased power. Further modifications included moving the inboard brakes outboard and altering the AC Ace 2.6 steering box to make more room for the engine.
The Cobra Mark 1 – a prototype was fitted with a small block Ford 260 cu in (4.3 L) engine. Finally in late summer 1965 about 528 units of the Cobra Mark II are produced using a Ford Windsor 289 cu in. engine. The suspension is a transverse leaf spring design and the car is fitted with rack and pinion steering. The steering rack is from an MGB design and the steering column is the same as the new VW beetles’.
This is the car that dominated the U.S. domestic race series (USRRC) for three years with only one lost race. On other racing circuits the car didn’t fare as well because of poor aerodynamics. Shelby went back to work with the engineers on a coupe. It was an eleventh hour decision to put a Ford 427 cu in (7.0 L) over the Ford 390 with very little time to develop a vehicle to race. Shelby had tried a 390 in an earlier Mark II prototype that failed to finish in Sebring – the driver of the Mark II 390 gave it a nickname of “The Turd” and said it was not drivable.
Detroit Ford worked with Shelby on the Mark III. They made a new 4’ (102 mm) tubular chassis with coil spring suspension with wider fenders, a larger radiator, and fitted it with a side oiler 427 (7.0 L) engine rated at 425 bhp (317 kW). The competition model will do 185 mph (298 km/h) while the street legal model reaches 164 mph (262 km/h). Production started on the competition version of the Cobra Mark III in January 1965. The Shelby race team did not get to race the car although there were many private race teams that had success with the Mark III into the ‘70’s. There were 31 remaining unsold Mark III S/C (semi-competition) units that were detuned, fitted with windshields, and then sold for street use.
There was one of two only original “Super Snake” 1966 Cobra Mark III 427’s sold for a record $5.5 million U.S., for this one of a kind 800 horse power version, at a Barrette-Jackson Collector Car Auction in Scottsdale, Arizona on January 21, 2009.
Shelby wanted his Cobra to beat Corvettes and the car accomplished that at Riverside International Raceway on February 02, 1963. The Cobra passed the Corvettes, Jaguars, Porches, and Maseratis in the historic victory. One AC Cobra coupe was clocked at 299 km/h (186 mph) on the M1 Motorway in the U.K. and this incident caused the British government to impose a 110 km/h (70 mph) speed limit on their freeways which up until that point had no speed limit.