Shelby Cobra 427

AC Cobra
AC Cobra MkIII
Overview
Manufacturer	AC Cars Shelby American
Also called	Shelby AC Cobra Shelby Cobra
Assembly	Thames Ditton, Surrey, England Los Angeles, California, USA
Body and chassis
Body style	2-door roadster
Layout	FR layout
Chronology
Predecessor	AC Ace
Successor	AC MK IV

MkI
CSX2000 – The first Cobra completed by Shelby
Overview
Production	1962–63
Powertrain
Engine	260 or 289 cu in (4.3 or 4.7 L) V8
Dimensions
Wheelbase	90 in (2,286 mm)
Length	151.5 in (3,848 mm)
Width	61 in (1,549 mm)
Height	49 in (1,245 mm)
Curb weight	2,019 lb (916 kg)

MkII
MkII 289 (FIA Roadster)
Overview
Production	1963–65
Powertrain
Engine	289 cu in (4.7 L) V8
Dimensions
Wheelbase	90 in (2,286 mm)
Length	151.5 in (3,848 mm)
Width	61 in (1,549 mm)
Height	49 in (1,245 mm)
Curb weight	2,315 lb (1,050 kg)

MkIII
1966 AC Cobra 427 (North America)
Overview
Production	1965–67
Powertrain
Engine	427 or 289 cu in (7.0 or 4.7 L) V8
Dimensions
Wheelbase	90 in (2,286 mm)
Length	156 in (3,962 mm)
Width	68 in (1,727 mm)
Height	48 in (1,219 mm)
Curb weight	2,355 lb (1,068 kg)

The AC Cobra, sold as the Shelby Cobra in the United States of America, is an Anglo-American sports car with a Ford V8 engine, produced intermittently in both the UK and United States of America since 1962.

Like many British manufacturers, AC Cars had been using the Bristol straight-6 engine in its small-volume production, including its AC Ace two-seater roadster. This had a hand-built body with a steel tube frame, and aluminium body panels that were made using English wheeling machines. The engine was a pre-World War II design by BMW which by the 1960s was considered dated. Bristol decided in 1961 to cease production of its engine and instead to use Chrysler 313 cu in (5.1 L) V8 engines. AC started using the 2.6 litre Ford Zephyr engine in its cars.

In September 1961, American automotive designer Carroll Shelby wrote to AC asking if they would build him a car modified to accept a V8 engine. AC agreed, provided a suitable engine could be found. Shelby went to Chevrolet to see if they would provide him with engines, but not wanting to add competition to the Corvette they said no. However, Ford wanted a car that could compete with the Corvette and they happened to have a brand new engine which could be used in this endeavor: the Windsor 221 in³ (3.6 L) engine – a new lightweight, thin-wall cast small-block V8. Ford provided Shelby with two engines.

In January 1962 mechanics at AC Cars in Thames Ditton, Surrey designed the "AC Ace 3.6" prototype with chassis number CSX2000.

AC had already made most of the modifications needed for the small-block V8 when they installed the 2.6 litre inline 6 Ford Zephyr engine, including the extensive rework of the AC Ace's front end bodywork. The only modification of the front end of the first Cobra from that of the "AC Ace 2.6" was the steering box, which had to be moved outward to clear the wider V8 engine.

The most important modification was the fitting of a stronger rear differential to handle the increased engine power. A Salisbury 4HU unit with inboard disc brakes to reduce unsprung weight was chosen instead of the old E.N.V. unit. It was the same unit used on the Jaguar E-Type. After testing and modification, the engine and transmission were removed and the chassis was air-freighted to Shelby in Los Angeles on 2 February 1962, By this time the small-block's displacement was increased to 260 in³ (4.3 L).