AC Cars Cobra 260 Mark I
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Car producer : |
AC Cars |
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Model: |
Cobra 260 Mark I |
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Year: |
1962 |
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Type: |
Roadster |
Production proved to be easy, since AC had already made most of the modifications needed for the small-block V8 when they installed the 2.6 L Ford Zephyr engine, including the extensive rework of the AC Ace's front end bodywork. The most important modification was the fitting of a stronger rear differential to handle the increased engine power. A Salisbury 4HU unit with inboard disk brakes to reduce unsprung weight was chosen instead of the old ENV unit. It was the same unit used on the Jaguar E-Type. On the production version, the inboard brakes were moved outboard to reduce cost. 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 motor.
AC exported completed, painted and trimmed cars (less engine and gearbox) to Shelby who then finished the cars in his workshop in Los Angeles by installing the engine and gearbox and correcting any bodywork flaws caused by the car's passage by sea. A small number of cars were also completed on the East Coast of the USA by Ted Hugus in Pennsylvania.
The first 75 Cobra Mark I (including the prototype) were fitted with the 260 cu in (4.3 L). The remaining 51 Mark I model were fitted with a larger version of the Windsor Ford engine, the 289 cu in (4.7 L) V8. In late 1962 Alan Turner, AC's chief engineer completed a major design change of the car's front end to accommodate rack and pinion steering while still using transverse leaf spring suspension.
The new car entered production in early 1963 and was designated Mark II. The steering rack was borrowed from the MGB while the new steering column came from the VW Beetle. About 528 Mark II Cobras were produced to the summer of 1965 (the last US-bound Mark II was produced in November 1964).
The 289 cu in (4.7 L) leaf-spring Cobra dominated the US domestic race series (USRRC), with only one race lost in three years. The results in the FIA GT class were different. This was mainly due to the number of circuits that had much higher sustained speeds. Aerodynamics were more important and put the roadster at a disadvantage. As a result, coupe versions were built.
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 1 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 1970s. The remaining 31 unsold examples were detuned and fitted with wind screens for street use. Called S/C for semi-competition.
The AC Cobra was a financial failure that led Ford and Carroll Shelby to discontinue importing cars from England in 1967. AC Cars kept producing the coil-spring AC Roadster with narrow fenders, a small block Ford 289 and called the car the AC 289. It was built and sold in Europe until late 1969. AC also produced the AC 428 until 1973. The AC Frua was built on a stretched Cobra 427 MK III coil spring chassis using a very angular steel body designed and built by Pietro Frua. With the demise of the 428 and succeeding 3000ME, AC shut their doors in 1984 and sold the AC name to a Scottish company. The company's tooling, and eventually the right to use the name, were licensed by Autokraft, a Cobra parts reseller and replica car manufacturer owned by Brian A. Angliss.
With the gap closing between the 289 Cobra and its competitors, Shelby was looking to keep the Cobras firmly ahead of the competition for the 1965 season. In Ken Miles’ opinion, what the Cobra needed was a larger, more powerful engine. Luckily enough, Ford had the perfect engine for the job: the new 427–cubic inch V-8. Supported with a brand-new chassis with coil springs at all four wheels, the new 427 Cobra was sure to be just what was needed to keep Ferraris and Corvettes at bay on racetracks at home and abroad.
The Ace chassis numbers read AEX... "A" being the car series and "X" being for export with left-hand drive. Later with the introduction of the Bristol engine the chassis numbers ran "BEX..." When switching to the Ford 2.6 engine the Ace chassis numbers ran "RS..." for Ruddspeed as Ken Rudd may have been influential in the choice of engine. The first Cobra chassis was left hand drive and given the next letter in the alphabet,i.e. C. Then "SX" for "Shelby eXport" i.e. exported to USA. Therefore the numbers ran CSX... for all the US export Cobras. The four following numbers ran from 2000 sequentially. When the MKIII Cobra was built the identification ran from CSX3000, the 3 signifying coil spring suspension. For the European market the cars were built wholly by AC cars in Thames Ditton using engines and transmissions imported from Ford USA. These cars were given chassis numbers beginning "COB...." for "Cobra Britain" i.e. RHD home market and "COX..." for "Cobra Export" i.e. RHD export other than to USA. COB/COX cars had chassis numbers beginning with a 6 and then either a 0 to signify a leaf sprung chassis or a 1 to signify a coil sprung chassis
