Mention AC sports cars, and the average American auto enthusiast is likely to link the letters with the name Shelby. That would of course conjure the AC Shelby Cobra, an iconic combination of British roadster body, American Ford V-8, and the imagination of Texan Carroll Shelby.
But as you’ll learn in this article, AC’s sports car legacy goes deeper than being party to the Cobra phenomenon in the 1960s. This small British firm has a respectable performance portfolio of its own, and a history that dates to 1900.
That’s when Autocarriers was established in England to assemble automobiles. It became AC in 1922 and had great success with an efficient little three-wheel van powered by a one-cylinder engine. It had another hit with a 2.0-liter six-cylinder engine introduced in 1919. Despite these bright spots, however, the company seemed prone to stagnation; the six-cylinder, for example, was in production until 1963.
The Great Depression and World War II were particularly unkind to AC, and it took the AC Ace of 1953 to turn things around. Based on a race car, good looking, and making fine use of that evergreen six, the Ace and its Aceca coupe companion were strong sellers. An engine transplant in 1957 created the faster AC Ace-Bristol and AC Aceca-Bristol. These six-cylinder sports cars retained the Ace’s handsome looks and were prelude to the V-8 AC Shelby Cobras, which emerged in 1962.
Not content to leave all the V-8 glory to Shelby, AC in 1965 created the AC 428. This was based on the Cobra chassis, but was no rip-roaring roadster. Instead, AC added six inches to the Cobra’s wheelbase and had Italian coachbuilder Frua fashion a snug fastback coupe body. Underhood was Ford’s 345-horsepower 428-cubic-inch V-8.
The AC 428, which also offered a convertible body, was a valiant attempt at an exotic GT, but never captured the imagination of enough buyers who could afford its steep price.
Still, it showed that AC was more than just a Cobra donor, even while it lived in the Cobra’s shadow. We'll get started on the next page with the AC Ace and Aceca.
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AC Ace and Aceca
The Ace roadster and companion Aceca were AC's first proper cars. Although tiny AC of Thames Ditton (near London) had built up a fine reputation by the early Fifties, it had developed a very staid image. Reason: its products were hopelessly behind the times. For example, its existing 2.0-liter car retained old-fashioned beam-axle front suspension, and the firm’s light-alloy six-cylinder engine dated back to 1919. AC owners Charles and Derek Hurlock were desperately looking for inspiration and a new model. Fortunately for us, they found both in the AC Ace and Aceca.
The result was AC’s sudden transformation into a successful sports-car builder, though it happened almost by chance. On a “friend of a friend” basis, the hand-built Tojeiro, a British racing sports car, was demonstrated to the Hurlocks, who promptly bought up the production rights and began making a road car of it. In fact, they tried two Tojeiros, one with a race-tuned Lea-Francis engine, the other with a 2.0-liter Bristol unit.>
The basis of the Tojeiro design was a simple ladder-style chassis built up of large diameter tubes and with wishbone and transverse-leaf-spring independent suspension front and rear. The race cars were graced with sleek two-seat “barchetta” bodies unashamedly modelled on those of the most recent racing Ferraris. What attracted the Hurlocks to the Tojeiro design was that little investment would be needed to tool up for chassis production, while the body could easily be produced at AC’s own coachbuilding facility.
By using an evolution of the ancient 2.0-liter six and a Moss gearbox, the Hurlocks were able to transform the racing Tojeiro into a relatively civilized roadgoing sports car. The project came together with astonishing speed.
The deal wasn’t hatched until the summer of 1953, yet the prototype, called AC Ace, was displayed at the London Motor Show in October and deliveries began the following year. The only real changes made in that frenzied development period were raising the original headlamp position (to meet international regulations for minimum height) and abandoning rack-and-pinion steering for a cam-gear system.
AC’s light-alloy overhead-cam engine, which had a mere 40 horsepower at 3000 rpm when introduced, was persuaded to produce 85 bhp at 4500 rpm for the AC Ace, enough to give the graceful new car a top speed of 103 mph. In the next few years, this remarkable old soldier would be tuned even more, to 90 bhp in 1955, and finally to 102 bhp in 1958.
With the open two-seater in production (later to become even more famous as the basis of the Shelby Cobra), AC decided to produce a fastback coupe version. This was the AC Aceca, its name, like Ace, revived from a famous AC of the Thirties. Revealed in late 1954 and in production by mid-1955, the AC Aceca, naturally enough, looked rather like Ferrari’s contemporary 166 and 212 models, a happy coincidence.
Once the AC Ace and AC Aceca were established, AC was up to building five cars a week. The chassis soon had such a good reputation that there were persistent demands for more power. With the AC engine near the end of its development life, alternative power had to be found, and AC eventually “bought in” the ex-BMW Bristol engine (see Ace- and Aceca-Bristol).
Nevertheless, and in spite of in-house competition from other derivatives, the AC-engined Ace and Aceca sold steadily until the autumn of 1963, by which time Thames Ditton was preoccupied with building engineless Cobras for Carroll Shelby in California.
Both models improved along the way. Front disc brakes were fitted from 1956-57, at which time an electrically actuated overdrive became optional. Later, the old Moss gearbox was dropped in favor of Triumph TR3A gears inside a case of AC’s own design. As a halfway measure between the two body types, a detachable hardtop was also made available for the AC Ace.
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AC Ace-Bristol and Aceca-Bristol
British race-driver Ken Rudd constructed the very first Ace-Bristol, but his hybrid was quickly adopted by the AC factory. First shown in autumn 1956, the AC Ace-Bristol and the companion AC Aceca-Bristol were in production by the spring of 1957. Because it was not only more powerful than AC’s own engine but capable of a lot more power-tuning, the Bristol unit made these cars, especially the Ace, much more suited for competition.
The roots of the AC Ace-Bristol design go back to the Thirties, when BMW engine design chief Fritz Feider produced a series of six-cylinder engines that culminated in the 1971-cc unit of the fabled 328. After World War II, Bristol of England “acquired” the design by somewhat dubious means (see Bristol Sports Cars) and manufactured it in the UK. By the mid-1950s, Bristol was happy to supply this noble engine to other automakers.
Complete with three downdraft Solex carburetors, the Bristol engine was tall but fit comfortably under the AC Ace-Bristol and AC Aceca-Bristol hood. It had pushrod overhead valve actuation (via complex linkages), part-spherical combustion chambers, and a very long stroke. Despite all this, it was amazingly flexible and high-revving.
For its AC application the engine was normally supplied in 105-horsepower “100C2” guise, but it could also be supplied with 120, 125, or 130 bhp. All versions teamed with Bristol’s own 4-speed manual gearbox, but apart from this, very few changes were made -- or needed -- for the transplant.
Compared with the AC-engine cars, the Bristol-powered Ace and Aceca had a lot more performance but were only a few pounds heavier, so they generally recorded similar fuel consumption figures. It was thus not surprising that though more expensive, they soon began outselling the earlier models, and eventually came to dominate the scene at Thames Ditton.
Naturally, chassis and other improvements were shared with the AC-engine cars. Both the AC Ace-Bristol and AC Aceca-Bristol were offered right from the start with Laycock overdrive (which operated on top, third, and second gears) as an option, and got front-wheel disc brakes as standard during 1957.
Although basic styling was not changed, the AC Ace-Bristol could be ordered with a curved, instead of flat, windshield beginning in 1958. You could also order a cowl for covering part of the radiator air intake, which reduced drag slightly and increased top speed to more than 120 mph.
In 1961, Bristol dropped a bombshell on the British specialty car market by announcing its new 407 with Chrysler hemi V-8 power -- and would soon phase out the old six. This meant that the AC Ace-Bristol and AC Aceca-Bristol were living on borrowed time and that AC needed to find an alternative engine fast. Eventually, AC wedged in the 2553-cc six from the British Ford Zephyr (allied to a Moss gearbox), offered in various stages of tune from 90 to 170 bhp (SAE). It proved very unsuccessful though: only 46 such cars were ever produced.
By 1962, assembly of the Bristol-engine cars was cut back to accommodate the buildup of Shelby Cobra production, though the last of the type wasn’t actually built until spring 1964.
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It was in 1965, as Cobra sales peaked, that the AC company had its next bright idea -- the AC 428. The latest coil-spring Cobra chassis provided excellent roadholding and could be tuned for a softer, more “boulevard” ride than in the sports cars. Why not, thought Derek Hurlock, use it as the basis for a modern, luxuriously equipped GT?
Hurlock began scouting the various specialist coachbuilders and finally chose the Italian house of Frua. For its new GT, AC merely lengthened the Cobra wheelbase by six inches -- easy to do with such a simple parallel-tube layout -- and slotted in Ford’s 428-cubic-inch big-block V-8.
As a concession to its softer, more refined character, the new model would be offered with Ford’s C-6 3-speed automatic transmission as well as manual gearbox. Christened AC 428, the car was considerably bulkier than previous ACs, yet deliberately designed as a two-seater. Perhaps AC’s unhappy experience with the 2 + 2 Greyhound coupes of 1959-1963 had something to do with this decision.
In other respects, the new AC 428’s chassis was like that of the Mark III Cobra, with four-wheel disc brakes, all-independent suspension via coil-spring/damper units and wishbones, and rack-and-pinion steering, though center-lock wire wheels were chosen instead of cast alloys. Despite hefty curb weight, there was no provision for power steering.
The first AC 428, a prototype convertible, was revealed at the London Motor Show in 1965, but much more development work was needed before sales actually began over a year later. By then, the convertible had been joined by a glassy fastback coupe with the same lower-body styling.
In overall appearance, the AC 428 was much like the contemporary Maserati Mistral, also a Frua design. Frua at the time was also supplying bodies to Monteverdi, and since AC didn’t actually impose any of its own styling ideas, the AC 428’s similarity was, perhaps, no surprise. It is said that some body panels and glass were shared by all three.
The AC 428 was much larger and heavier than any previous AC. It was certainly a lot more expensive. The main reason was all the shipping involved. Building the AC 428 required importing Ford drivetrains from Detroit; building and then sending the rolling chassis to Italy, where Frua added the body and completed final assembly; then bringing the finished cars back to the UK for final testing and inspection. As they used to say at Avanti, the car traveled so much during production that it was out of warranty by the time it reached the customer.
For all that, sales were meager. Who, after all, was likely to buy an Italian-bodied American-powered car from a tiny British concern when they could get a genuine Italian thoroughbred with a high-revving twincam engine and a famous badge for the same money? By 1973, when the car was dropped, only 58 coupes and 28 convertibles had been produced. The oil crisis, existing and impending EEC and USA regulations, an unsuccessful battle against labor problems in Italy, and AC’s inability to undercut the pricing of firms like Aston Martin all contributed to the AC 428’s demise.
Few of these cars seem to have survived. Yet though rarer than original Cobras, their collector-market prices have long been quite reasonable, which suggests that interest has peaked. A pity, for the AC 428 is a lot faster than you’d think and has bags of style and exclusivity. One can only wonder how it might have fared with a “designer” label.