The AC Cobra, also known colloquially
as the Shelby Cobra in North America, is an Anglo-American sports
car that was produced during the 1960s.
Like many British specialist manufacturers, AC Cars had been using
the smooth, refined Bristol straight-6 engine in its small-volume
production, including its AC Ace 2-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 of BMW which by the 1960s was considered
dated. Bristol decided in 1961 to cease production of its engine and
instead to use Chrysler 331 cid (5.4 L) V8 engines.
AC started using the 2.6 litre Ford Zephyr engine in its cars. In
September 1961, Shelby airmailed AC a letter asking them if they
would build him a car modified to accept a V8 engine. AC agreed,
provided a suitable engine could be found. He first went to
Chevrolet to see if they would provide him with engines, but not
wanting to add competition to the Corvette they said no. Ford
however, wanted a car that could compete with the Corvette and they
happened to have a brand new thin-wall small-block engine which
could be used in this endeavour. It was Ford's 260 in³ HiPo (4.2 L)
engine – a new lightweight, thin-wall cast small-block V8 tuned for
high performance. Ford provided Shelby with two 260ci engines.
In January 1962 mechanics at AC Cars in Thames Ditton, Surrey fitted
the prototype chassis CSX0001 with a 260ci Ford V8. 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. His team fitted it with an engine and transmission in less
than eight hours at Dean Moon's shop in Santa Fe Springs,
California, and began road-testing.