The Sunbeam Tiger is a high-performance V8 version of the British Rootes Group's Sunbeam Alpine roadster, designed in part by American car designer and racing driver Carroll Shelby and produced from 1964 until 1967. Shelby had carried out a similar V8 conversion on the AC Cobra, and hoped to be offered the contract to produce the Tiger at his facility in America. Rootes decided instead to contract the assembly work to Jensen at West Bromwich in England, and pay Shelby a royalty on every car produced.
Two major versions of the Tiger were built: the Mark I (1964–1967) was fitted with the 260 cu in (4.3 L) Ford V8; the Mark II, of which only 633 were built in the final year of Tiger production, was fitted with the larger Ford 289 cu in (4.7 L) engine. Two prototype and extensively modified versions of the Mark I competed in the 1964 24 Hours of Le Mans, but neither completed the race. Rootes also entered the Tiger in European rallies with some success, and for two years it was the American Hot Rod Association's national record holder over a quarter-mile drag strip.
Production ended in 1967 soon after the Rootes Group was taken over by Chrysler, which did not have a suitable engine to replace the Ford V8. Owing to the ease and affordability of modifying the Tiger, there are few remaining cars in standard form.
The Sunbeam Tiger was a development of the Sunbeam Alpine series I, introduced by the British manufacturer Rootes in 1959. Rootes realised that the Alpine needed more power if it was to compete successfully in world markets, but lacked a suitable engine and the resources to develop one. The company approached Ferrari to redesign the standard inline-four engine, recognising the cachet that "powered by Ferrari" would likely bring. Negotiations initially went well, but ultimately failed.
In 1962 racing driver and Formula 1 champion Jack Brabham proposed to Rootes competition manager Norman Garrad the idea of fitting the Alpine with a Ford V8 engine,[a] which Garrad relayed to his son Ian, then the West Coast Sales Manager of Rootes American Motors Inc. Ian Garrad lived near Carroll Shelby's Shelby American operation, which had done a similar V8 conversion for the British AC Cobra.
According to journalist William Carroll, after measuring the Alpine's engine bay with "a 'precision' instrument of questionable antecedents" – a wooden yardstick – Ian Garrad despatched his service manager Walter McKenzie to visit the local new car dealerships, looking for a V8 engine that might fit. McKenzie returned with the news that the Ford 260 V8 engine appeared to be suitable, which apart from its size advantage was relatively light at 440 lb (200 kg). Ian Garrad asked Shelby for an idea of the timescale and cost to build a prototype, which Shelby estimated to be eight weeks and $10,000. He then approached Brian Rootes, head of sales for the Rootes Group, for funding and authorisation to build a prototype, to which Brian Rootes agreed.
Ian Garrad, impatient to establish whether the conversion was feasible, commissioned racing driver and fabricator Ken Miles to build another prototype as quickly as he could. Miles was provided with a budget of $800, a Series II Alpine, a Ford V8 engine and a 2-speed automatic transmission, and in about a week he had a running V8 conversion, thus proving the concept.
Shelby began work on his prototype, the white car as it came to be known, in April 1963, and by the end of the month it was ready for trial runs around Los Angeles. Ian Garrad and John Panks, director of Rootes Motors Inc. of North America, tested an early version of the car and were so impressed that Panks wrote a glowing report to Brian Rootes: "we have a tremendously exciting sports car which handles extremely well and has a performance equivalent to an XX-K Jaguar[b] ... it is quite apparent that we have a most successful experiment that can now be developed into a production car."
Provisionally known as the Thunderbolt, the Shelby prototype was more polished than the Miles version, and used a Ford 4-speed manual transmission. The Ford V8 was only 3.5 inches longer than the Alpine's 4-cylinder engine it replaced, so the primary concern was the engine's width. Like Miles, Shelby found that the Ford V8 would only just fit into the Alpine engine bay: "I think that if the figure of speech about the shoehorn ever applied to anything, it surely did to the tight squeak in getting that 260 Ford mill into the Sunbeam engine compartment. There was a place for everything and a space for everything, but positively not an inch to spare."
All Rootes products had to be approved by Lord Rootes, who was reportedly "very grumpy" when he learned of the work that had gone into the Tiger project without his knowledge. He agreed to have the Shelby prototype shipped from America in July 1963 for him and his team to assess. He insisted on driving the car himself, and was so impressed that shortly after returning from his test drive he contacted Henry Ford II directly to negotiate a deal for the supply of Ford V8 engines. Rootes placed an initial order for 3000, the number of Tigers it expected to sell in the first year, the largest single order Ford had ever received for its engines from an automobile manufacturer. Not only did Lord Rootes agree that the car would go into production, but he decided that it should be launched at the 1964 New York Motor Show, only eight months away, despite the company's normal development cycle from "good idea" to delivery of the final product being three to four years.
Installing such a large engine in a relatively small vehicle required some modifications, although the exterior sheet metal remained essentially the same as the Alpine's. Necessary chassis modifications included moving from the Burman recirculating ball steering mechanism to a more modern rack and pinion system.
Although twice as powerful as the Alpine, the Tiger is only about 20% heavier, but the extra weight of the larger engine required some minor suspension modifications. Nevertheless, the Tiger's front-to-back weight ratio is substantially similar to the Alpine's, at 51.7/48.3 front/rear.
Shortly before its public unveiling at the New York Motor Show in April 1964 the car was renamed from Thunderbolt to Tiger, inspired by Sunbeam's 1925 land-speed-record holder.[c]
Shelby had hoped to be given the contract to produce the Tiger in America, but Rootes was somewhat uneasy about the closeness of his relationship with Ford, so it was decided to build the car in England. The Rootes factory at Ryton did not have the capacity to build the Tiger, so the company contracted the job to Jensen in West Bromwich. Any disappointment Shelby may have felt was tempered by an offer from Rootes to pay him an undisclosed royalty on every Tiger built.
Jensen was able to assume production of the Tiger because its assembly contract for the Volvo P1800 had recently been cancelled. An additional factor in the decision was that Jensen's chief engineer Kevin Beattie and his assistant Mike Jones had previously worked for Rootes, and understood how the company operated. The first of 14 Jensen-built prototypes were based on the Series IV body shell, which became available at the end of 1963.
The Tiger went into production in June 1964, less than a year after completion of the Shelby prototype. Painted and trimmed bodies were supplied by Pressed Steel in Oxfordshire, and the engines and gearboxes directly from Ford in America. Installing the engine required some unusual manufacturing methods, including using a sledgehammer to bash in part of the already primed and painted bulkhead to allow the engine to be slid into place. Jensen was soon able to assemble up to 300 Tigers a month, which were initially offered for sale only in North America. The first few Tigers assembled had to be fitted with a Borg-Warner 4-speed all-synchromesh manual gearbox, until Ford resolved its supply problems and was able to provide an equivalent unit as used in the Ford Mustang.
Several performance modifications were available from dealers. The original 260 CID engine was considered only mildly tuned at 164 hp (122 kW), and some dealers offered modified versions with up to 245 hp (183 kW) for an additional $250. These modifications were particularly noticeable to the driver above 60 mph (97 km/h), although they proved problematic for the standard suspension and tyres, which were perfectly tuned for the stock engine. A 1965 report in the British magazine Motor Sport concluded that "No combination of an American V8 and a British chassis could be happier."
Production reached 7128 cars over three distinct series. The factory only ever designated two, the Mark I and Mark II, but as the official Mark I production spanned the change in body style from the Series IV Alpine panels to the Series V panels, the later Mark I cars are generally designated Mark IA by Sunbeam Tiger enthusiasts. The Mark II Tiger, fitted with the larger Ford 289 cu in (4.7 L), was intended exclusively for export to America and was never marketed in the UK, although six right-hand drive models were sold to the Metropolitan Police for use in traffic patrols and high-speed pursuits; four more went to the owners of important Rootes dealerships.
All Tigers were fitted with a single Ford two barrel carburetor. The compression ratio of the larger Mark II engine was increased from the 8.8:1 of the smaller block to 9.3:1. Other differences between the versions included upgraded valve springs (the 260 had developed a reputation for self-destructing if pushed beyond 5000 rpm), an engine-oil cooler, an alternator instead of a dynamo, a larger single dry plate hydraulically operated clutch, wider ratio transmission, and some rear-axle modifications. There were also cosmetic changes: speed stripes instead of chrome strips down the side of the car, a modified radiator grille, and removal of the headlamp cowls. All Tigers were fitted with the same 4.5 in (110 mm) wide steel disc bolt-on wheels as the Alpine IV, and Dunlop RS5 4.90 in × 13 in (124 mm × 330 mm) cross-ply tyres. The lack of space in the Tiger's engine bay causes a few maintenance problems; the left bank of spark plugs is only accessible through a hole in the firewall, normally sealed with a rubber bung, and the oil filter was relocated from the lower left on the block to a higher position on the right-hand side, behind the alternator.
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