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. 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 litre inline 6 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 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. 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 engine. 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 Ed Hugus in Pennsylvania, including the first production car; CSX2001. The first 75 Cobra Mk1 models (including the prototype) were fitted with the 260 cu in (4.3 L).[9] The remaining 51 Mk1 models 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.