The Prototype AC Cobra Sports Car

A detailed review of The Prototype AC Cobra Sports Car, covering technical data, performance, features, comparisons, and historical development of this classic car

from Classic to Modern

It was hand built, with aluminium body panels fitted to a frame comprised of steel tubing. Early models were fitted with AC’s own 2 litre, straight 6-cylinder, overhead cam engine, that was originally designed in 1919.

In 1956, Bristol Cars made available their own 2 litre, in-line 6-cylinder engine, with three SU carburettors, as an alternative unit. Production of the Ace continued with this engine until 1961, when the unit was withdrawn by Bristol. That same year, a Ruddspeed tuned 2.6 litre, in-line 6-cylinder engine, as used in the Ford Zephyr saloon, was fitted to the Ace. This unit produced 170 bhp, had a top speed of 130 mph, and was capable of 0-60 mph in 8.1 secs. Furthermore, prior to fitting the 2.6 litre engine, AC had made a number of modifications to the Ace chassis in anticipation of adding a still larger engine, such as a 3.6 litre unit. This also included restyling the front section of the body to make allowances for the increased size and weight of the larger engine. Whilst racing in Europe and the Americas in the 1950’s, Carroll Shelby’s ambition was to create the world’s fastest sports car. However, following his 1959 Le Mans win for Aston Martin, he was forced to retire on health grounds mercedes benz car covers.

When Bristol announced they would discontinue their 2 litre engine, it left the AC Ace potentially without an engine. In September 1961, Carroll Shelby, a US car designer and race driver, on hearing this, approached AC with a request to modify an Ace so that it could accept a large V8 engine. Having been given the go ahead by AC on the proviso that he found a suitable engine, Shelby first approached Chevrolet. This request was rejected, since Chevrolet felt that this would provide unnecessary competition for its own Corvette sports car. On the other hand, Ford was very interested, and was keen to be involved with a car that would compete with the Corvette. In the meantime, AC turned to earlier engineering drawings for an AC Ace fitted with a 3.6 litre (221ci) engine. Consequently, AC produced the first Cobra with a Ford 221 ci V8 engine, which was the same size, externally, as the Ford 260 ci V8. In 1962, the existing chassis was modified, and this prototype chassis CSX2000 was fitted with a 260 ci HiPo (high performance) Ford V8 engine and Borg Warner all synchromesh four speed gearbox, on loan from Ford in the UK.

Upon receipt, a 260 ci Ford V8 engine and gearbox were fitted, and road testing of the first prototype got under way. In April 1962, the first Cobra, with chassis CSX2000, was introduced at the New York Motor Show where it was a great success, with orders coming in faster than Shelby could build them. Although the car was called the AC Cobra in the UK, in the US, it was better known as the Shelby Cobra. Body styling of the early Cobras was almost identical to the AC Ace, apart from a smaller grille and flared wheel arches, on the former, to accommodate wider tyres. Throughout its life, the Cobra’s chassis was never rigid enough to handle the cars’ massive torque, which made it all the more challenging to drive.  It weighed slightly more than the 221 unit, and developed 164 bhp at 4400 rpm, and 258 ft/lbs of torque at 2200 rpm. Early Cobras used the HiPo version with raised compression, more aggressive camshaft timing, and a four barrel carburettor. This engine developed 260 bhp at 5800 rpm, and 269 ft/lbs of torque at 4800 rpm.

The TVR 3000M Turbo and 5000M Sports Car

The TVR 3000M Turbo

In order to improve the performance of the 3000M, TVR approached the company Broadspeed to produce a turbocharged version of the Ford Essex V6 engine. Interestingly, the highly modified engine fitted into the engine bay of the 3000M with little trouble. Consequently, designated the 3000M Turbo sports car, it was premiered at the 1975 British International Motor Show at Earl’s Court in London. These cars were fitted with Koni shock absorbers, wider wheels, and a reduced compression ratio.

A total of 20 of the 3000M Turbos were built. This was later followed by 30 of the Taimar variant. Finally, 13 of the 3000S version were built. Of these, three of the Taimar, and one 3000S Turbos were converted into Special Equipment (SE) variants. They were fitted with leather trim, flared wheel arches, special alloy wheels, and limited slip differential. With a compresion ratio of 8.0:1, a turbocharger blowing at 9 psi, and fitted with a single Webber twin choke carburettor, the turbocharged engine developed 230 bhp at 5500 rpm, and 273 ft/lbs of torque at 3500 rpm. This produced a top speed of 140 mph, and a 0-60 mph time of 5.7 secs. The turbocharger kicked in at 2700 rpm which meant that, below this, the car performed in the same way as a normal 3000M. In fact, the performance of the TVR 3000M Turbo actually gave the Porsche 911 three litre Turbo of the period a real run for its money. M-Series cars ended production in late 1979, with the 3000M Turbo returning TVR to the status of a builder of Supercars.

The TVR 5000M

In 1974, John Wadham, who ran the Canadian-based TVR importer in the US, set about replacing the Triumph 2.5 litre, straight six engine, fitted to a 2500M, with a 5 litre (302 cubic inch), Ford Windsor V8 unit. This involved the use of different engine mountings, an alternative radiator, and stiffer springs. A Borg Warner four speed gearbox was used, and the rear differential was sourced from the Chevrolet Corvette. Designated the TVR 5000M sports car, it was debuted at the 1975 Toronto International Motor Show. However, that same year, a severe fire damaged the TVR factory in the UK, with the result that production was halted. Notwithstanding, as a gesture of support in the company, John Wadham paid in advance for the order of six cars to be shipped to him for further assembly into the 5000M.

As it turned out, his action may have contributed in securing the company’s future. Subsequently, TVR shipped five M-Series fixed head coupes, that excluded engines or gearboxes, to the US importer for conversion into the 5000M. Furthermore, John Wadham himself converted a further three cars, that had just arrived from the UK, and contained damaged Ford Essex V6 engine blocks. In 1978, TVR built a limited edition of just one unit, less engine and gearbox, that was painted in white, and featured a brown stripe. This had 5000M identifiable markings, and was dispatched to John Wadham for the addition of the V8 engine. It has been estimated that only 9 units of the original 5000M were built up to 1978. However, beyond 1980, six TVR Taimars have had their existing engines replaced by the V8 unit. This marked the end of the TVR 3000M Turbo and 5000M. Perhaps this stroll down memory lane might have answered, or at least shed light on, a possible question:

Which TVR Sports Car is Your Favourite?

However, should this question still remain unanswered, I will be reviewing, in some detail, in future articles within this website, the entire range of TVR sports cars which were featured in the memorable era spanning 1946 to 1967.

The AC Sports Car

A review of The AC Sports Car, covering development, important features, and technical data of each model in the range, from the AC 2-litre to the 3000ME. In this Article, I offer a nostalgic review of The AC Sports Car, one of an elite group of classic cars, which was manufactured during the period 1947 to 1984+. The Auto-Carriers (hence AC) Company was formed in 1903.

The AC 2 Litre

After WW2, the company came into its own with the production of the AC 2-Litre. It was a two and four door saloon which, from 1949, was offered as a drop head coupe version. It used a 2 litre, 6-cylinder engine, with an aluminium head, and three SU carburettors. It incorporated aluminium body panels, on a wood frame, and fitted to a steel chassis.

The AC Ace

In 1953, the AC Ace was introduced, and it was this two seater that sealed the companies future reputation. It used an alloy body on a tubular frame and, interestingly, incorporated all-round, independent leaf spring suspension. Initially, the Ace used an outdated (post WW1) 2 litre, straight six, overhead cam engine. Finally, in 1961, a 2.6 litre “Ruddspeed” modified engine, as used (unmodified) in the Ford Zephyr saloon, became available. This used three Weber or SU carburtettors, and transformed the performance.

The Aceca offered the same choice of engines as in the Ace:

The AC 1991cc overhead cam engine

The 1971 cc unit from Bristol Cars

The 2553 modified Ford Zephyr unit

When production ended in 1963, 151 Aceca, 169 Aceca-Bristol, and 8 Ford-engined (2553 cc) models were built.

The AC Cobra

In 1961, AC was approached by Carroll Shelby to produce a modified car, based on the AC Ace chassis, that would accept a Ford V8 engine. He required a car that would compete with the Corvette Stingray in US car racing. Hence was born the AC Cobra. In 1962, the first 75 of the Mark 1 AC Cobra were fitted with the 4261 cc (260 cu in) engine. However, the remaining 51 Mark 1’s used the larger Ford 4727 cc (289 cu in) unit. In 1963, the Mark 2 AC Cobra was introduced, fitted with the Ford 4727 cc engine. By 1965, 528 of the Mark 2’s had been built. Finally, in 1965, the Mark 3 AC Cobra was launched, and was fitted with the ferocious 6997 cc (427 cu in) engine. By 1966, 306 of the Mark 3’s had been built. Carroll Shelby had always wanted the AC Cobra to be a “Stingray Beater”. In 1963, he got his wish at the Riverside International Raceway when a Cobra recorded its first ever victory, beating Stingrays, Porsche, Maserati and Jaguars.

Production of the classic AC Cobra ended in 1984.

The AC 3000ME

In 1979, the two seater AC 3000ME was launched at the London Motor Show. It had a glass fibre body on a steel chassis. The mid engined 3000ME used a 3 litre, Ford V6 engine positioned transversely. Only 71 cars were sold. This marked the end of the classic AC sports car. Beyond 2000, AC produced a number of exciting sports cars which, sadly, falls beyond the time frame of this review. Perhaps this stroll down memory lane might have answered, or at least shed light on, a possible question:

“Which AC Sports Car Is Your Favourite?”

However, should this question still remain unanswered, I will be reviewing, in some detail, in future articles within this website, the entire range of AC sports cars which were featured in the memorable era spanning 1958 to 1992.

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