Sports Car Challenge From America
A New General Motors Product Which May Affect Our Export Sales
Since the war Britain has found America to be receptive to British sports cars and useful export business has been conducted by M.G., Jaguar, Allard, Aston Martin and others. In a recent address, reported in Motor Sport last December, Sydney Allard remarked that the huge American automobile manufacturing concerns, tooled up for mass production of ordinary automobiles are unlikely to turn to the output of sports cars until such time as they are convinced that sporting America is able to absorb at least 20,000 such autos every year.
When this time comes, if it comes, the British sports-car manufacturer will face competition which so far has been lacking.
The rapidly increasing enthusiasm in the States for sports-car racing and, indeed, for the Sport in all its forms might be expected to bring appreciably closer the day when Britain will compete with the huge U.S. assembly plants for priority of sports-car sales.
So far only Briggs Cunningham has seriously set out to gain a hold on this market and his sports Cunningham is both expensive and in limited production. It has already gained victory in American sports-car races and finished third to the Jaguars at Le Mans last June.
Recently there have been signs that America’s big manufacturers may have sports-car production in mind. The tendency to use more and more powerful power units in ordinary American cars as a sop to the sales-executives’ power race, provides suitable engines for fast cars, and to this situation must be added the facts that American designers are getting better and better opportunities to improve chassis design through familiarity with racing requirements and that mass-production methods as commonly applied in the U.S. should enable the price of sports cars to be highly competitive, especially as suitably modified stock components would constitute the specification. America’s “soup shops” have taught that modern engines and transmissions can be suitably adapted to the needs of speed and high-power output.
Recently the American monthly Speed Age (now, alas, defunct, or, rather, replaced by Car Life) revealed that Chevrolet, a make which stemmed originally from racing, has produced a sports car, in the form of the Corvette.
This, low-slung Corvette convertible was exhibited at various motor shows in the fall of 1952 and last September it was shown officially to some fifty American newspapermen.
Now there are some significant facts about this smart, well-equipped glass-fibre two-seater Chevrolet. It is not intended as a competition sports car, but rather as a fast, comfortable, ornament-free high-performance vehicle. It seems that at General Motors’ busy Chevrolet factory, about 250 Corvettes were made during last year and this year, when the assembly line moves from the Flint factory to the St. Louis plant, the aim is an annual output of 12,000. It is expected that demand will call for an even greater output, as General Motors’ 7,600 dealers go about the business of selling American enthusiasts their first big output, high-performance, sports-car-handling convertible. And the Corvette sells for a mere $3,490.
The significant fact seems to be that already, from a car plant producing six chassis types, it has been possible to produce in three months two and a half times as many of these new Corvettes than Allard reckons to export Allard cars for a whole year. Moreover, General Motors could presumably gear-up production by 1955 to close on the figure at which Allard thinks it would be worth while for the U.S. to build sports car. This view receives confirmation from no less a person than Wm. Fish, General Sales Manager of the Chevrolet Division of the great General Motors combine, who is reported as saying: “Chevrolet is in the sports-car field for the life of the Company.”
Granted that the new Chevrolet Corvette is not a true sports car, is, in fact, a luxury convertible of high performance, the truth is that Paul R. Hayes, Managing Editor of Car Life, has given it as his opinion that although not designed to be raced, “the Corvette undoubtedly will be.” It has the lines of a very low, completely open, all-enveloping sports car when the “top” is down.
The basis of the Corvette is a new welded box-section chassis braced by a central “X”-member, above which the open propeller-shaft runs in a deep floor tunnel. Front independent suspension is of conventional Chevrolet pattern, but employing stiffer coil springs and shock-absorbers. Rear suspension is by 51-in.-long out-rigged semi-elliptic leaf springs. The hydraulic brakes have 11 in. diameter drums and the steering column is almost parallel to the ground to provide a near-vertical steering-wheel position. The two-spoke wheel asks about 3 1/2 turns, lock-to-lock, which is far higher gearing than the five or more turns called for in most American cars. The actual ratio is 16 to 1.
The chassis of the Corvette has a wheelbase of 8 ft. 6 in. and a reversed crab-track of 4 ft. 9 in. at the front, 4 ft. 11 in. at the back.
The power unit is the well-established six-cylinder, 3,850-c.c. overhead-valve Chevrolet “Blue Flame” engine, coupled to a modified Power Glide transmission. The engine has been altered in respect of having a high-lift camshaft, a vacuum-booster fuel pump, extra alloy-steel exhaust valves, three side-draught Carter carburetters feeding into a cast-alloy inlet manifold and a dual exhaust system. The power output is 160 b.h.p., but on production Corvettes this is being brought down to 150 b.h.p. at 4,200 r.p.m. (peak r.p.m. 5,000) on a compression-ratio of 8 to 1, to ensure adequate tractability in traffic.
The appearance of the Chevrolet Corvette is very pleasing to European eyes, at all events in its Press pre-view form, when the “Christmas-tree” men had not got at it. The bonnet is so low that the designer — who is Chevrolet’s Chief Engineer, E. N. Cole — has mounted the radiator inclined rearwards at 15 deg. and has, even then, had to put the header tank beside the engine, alongside and level with the valve cover.
Although automatic transmission has been used, because the hulk of American buyers demand this, the normal action of Power Glide has been changed to provide a change-up on full throttle which does not occur until 55 m.p.h. has been reached, while the over-riding selector lever is situated between the two bucket-type seats like the gear lever of a European sports-car.
A 3.55 to 1 final drive is used, as on normal Chevrolet models. The body is a sleek glass-fibre shell, to produce which dies valued at $400.000 have been installed. Composed of 56 separate pieces made at Detroit and Ohio, the body of the Corvette has 1/4 in. thick panels of 40 per cent, resin and 60 per cent, glass fibre, yet it is said to weigh 200 lb. less than an equivalent steel body. It actually weighs 411 lb. and the complete car, which is only 4 ft. high to the top of the generous windscreen and 13 ft. 11 in. in length, scales just over 25 cwt., distributed 50/50 between front and back wheels.
There are many clever aspects of the Corvette body. For instance, the door arm-rests can be lifted up to reveal a deep door pocket. The plastic bonnet hinges at the front. There is ample luggage space in the boot behind the 17-gallon fuel tank, there is a one-piece curved windscreen, and the instruments, if small, include five dials in addition to the larger, central speedometer. The grille is very modest for an American car and the disc wheels have imitation centre-lock hubs. The built-in headlamps are behind stone-guard covers. A push button in the metal beading between the seats releases a cover over the smell formed above the fuel tank, into which the convertible top becomes entirely concealed when not in use. The Corvette is available in any paint colour, but is normally supplied in Polo White. No bumpers are fitted.
Upholstery is in red plastic over foam rubber and the plastic side windows are removable.
Now what about performance? It seems that General Motors merely claim a speed of 100 m.p.h. plus. But testers assess the true top speed in the region of 110 m.p.h., to which we can add acceleration of the order of to 60 m.p.h. in under 11 seconds, in spite of automatic upward changes.
In price the Chevrolet Corvette compares in the States with our Jaguar XK120, and it seems likely that as production steps up it will be reduced to the price level of the Sunbeam Alpine, H.R.G., Allard Palm Beach, Austin Healey 100 and similar British sports cars. It certainly seems to possess a performance which will leave most of these cars behind, although it is no match for the XK120 and would have a tussle with the Austin Healey.
As a pointer or a straw-in-the-wind, the propensities of which British manufacturers would do well to watch, I think the Chevrolet Corvette is worth introducing to you. — W. B.
N.B.– Lesser “straws-in-the-wind ” may be found, perhaps, in the Kurtis Kraft, Cunningham, Edwards and Excalibur J.