Chevrolet Corvette Service Repair Manuals

1956-57 CORVETTE

1956 Corvette 2-dr. Roadster 2 passenger
1956 Corvette 2-dr. Roadster 2 passenger

It has often been stated that the Corvette lost money for the first 10 years of its life, 1953-63. That's strictly an unconfirmed rumor, and since General Motors does not talk about its losses, who's really to say?

But there's no doubt that those early Corvettes cost the company dearly, this at a time when the car showed very little promise of any financial payback. Early sales figures painted the bleakest of pictures: 3940 Corvettes sold in 1953-54, and a paltry 700 in 1955, even with the introduction that year of Chevy's landmark small-block V-8. Thus it is hardly any wonder that GM's bean counters talked seriously about killing the fledgling 'Vette.

Yet Chevrolet was not giving up quite yet. Why wouldn't Chevy let the Corvette die? Partly because some people in high places saw a future in it, and partly because GM would lose face and give up a market niche by dropping the Corvette so soon after Ford introduced the Thunderbird.

Those who are old enough to remember the Corvette's introduction and early years from 1953 through 1955 will recall that the car arrived with a distinctly odd focus. Or lack of focus, perhaps, for no one knew just what the Corvette was supposed to be or do. Was it a sports car? Not with Chevy's "Stovebolt Six" mated to the two-speed Powerglide automatic. Was it a factory hot rod? Hardly. It wasn't even much of a boulevard cruiser, and its $3523 base price in 1954 meant one could buy a Cadillac for about the same money. It's precisely that odd focus and ultimately the 'Vette's redefinition in the 1956-57 models that's of interest here. The transformation turned out to be a minor marvel -- something that happens rarely. It was brought about by just a handful of men, and it involved not only the Corvette's survival, but the car's coming of age.

GM design vice-president, Harley Earl, envisioned the first 'Vette as a $1800 runabout for college kids. He had in mind a car for his own teenage sons, Jim and Jerry. But the 1953-54 Corvette came in at over $3500, nearly double what Earl had originally intended, a big difference even by Ivy League standards. Consider also that a brand-new Chevy Bel Air sold for as little as $1830 in 1954.

After the Corvette's brush with death in 1955, all of a sudden, surprisingly, wondrously, the car not only survived -- but it actually took on a purpose. Its odd focus resolved itself into a real, honest-to-goodness American sports car. That transformation took place in model-years 1956-57. Until then, even with the V-8 in 1955, Chevy's glass two-seater remained essentially Harley Earl's motorama show car made streetable.

In 1956-57, at tremendous cost, Chevrolet turned the Corvette into a true sports car by giving it power, handling, reliability, looks, and a defined focus. Beyond that, the 'Vette also kept coming up with unexpected perks: a Duntov cam option, fuel injection, the competition SR-2, and the Sebring SS. Those were all expensive little forays into the unexpected, into hard-to-justify territory, but thanks to those true believers in high places, the Corvette came up very quickly from humble-pie beginnings to national -- and even international -- prominence.

The Corvette's godfather, of course, was Harley Jefferson Earl, all six-foot-four of him. A native Hollywood Californian, Earl as a young man had designed custom coachwork for movie stars. Taking note, GM president Alfred Sloan lured Earl to Detroit in 1925-26, giving him lots of money plus a free hand to set up a corporate styling department. Earl's Art & Colour Section soon became the largest, most influential automobile styling center in the world. Earl put his stamp on all General Motors cars from 1927 on, becoming in the process America's doyen of car design.

Earl towered over other men, both physically and figuratively. He was, among other things, GM's resident maverick. He wore loud clothes, drove low-slung cars, and knew intuitively what made cars sell. During his tenure, GM set the world standard in styling. Earl was loved, hated, respected, feared, and admired, sometimes all at the same time and by the same person.

After World War II, at the height of his powers, Earl began creating a series of showcars, initially to impress GM's directors at annual new-model unveilings in New York's Waldorf-Astoria Hotel ballroom. These semi-private Waldorf shows evolved into GM's free-to-the-public Motoramas, which became amalgams of futuristic show cars and live stage entertainment. Held yearly from 1949 to 1962, the Motoramas -- which mixed music, dance, showgirls, and cars -- were trucked to major cities across America, giving millions of people a chance to admire GM's wealth of ideas and technology.

One striking 1953 Motorama show car was the Chevrolet Corvette. Harley Earl didn't personally design that first (or any) Corvette, but he did deliver it by Caesarian section. He also sold the idea of producing it to GM management, while Chevrolet remained one of the marque's staunchest supporters. Harley Earl retired in 1958.

Another person in high places was Edward Nicholas Cole. He was a gentle man: cheerful, astute, thoughtful, kind, courteous, enthusiastic, engaging, and extremely capable. He grew up in Mame, Michigan, where his father ran a small dairy farm. As a teenager, Cole buzzed the countryside in his hot rods, among them a Saxon roadster and several Model T Fords. His father wanted him to become a lawyer, but Cole loved things mechanical and decided on a career in automotive engineering.

In the Depression year of 1933, after dropping out of the General Motors Institute for financial reasons, Cole was offered a job at Cadillac as a lab assistant. Sixteen years later, he emerged as that division's chief engineer. There he headed the team that engineered Cadillac's revolutionary, lightweight, overhead-valve V-8 for 1949.

Cole moved to Chevrolet in 1952, again as chief engineer. There he immediately boosted Chevy's technical staff from 850 to 2900 people, all needed to develop the 1955 V-8 and the all-new 1955 passenger cars and trucks. In 1953, Chevrolet decided to produce the Corvette, so Cole hired Zora Arkus-Duntov that spring to help vault Chevrolet past Ford in the performance arena. Ed Cole went on to become Chevrolet's general manager in 1956, then GM's president in 1967. He retired in 1974 and was killed in 1977 when his twin-engined Badger aircraft crashed in a snowstorm near Kalamazoo, Michigan.

It was during the Cole years that the Corvette arrived, survived, and eventually flourished. GM and Chevrolet were doing extremely well financially in the mid-Fifties, and that success played a major role in Corvette's survival. Also, Chevy's rivalry with Ford grew intense when Cole decided to pull away from Ford not only in sales, but also in raw performance. Until 1955, the average man in the street -- even if performance didn't mean that much to him -- viewed Ford as the hot rod and Chevy as the bank teller's car. That stereotypical image had for decades rested on Ford's lively flathead V-8 versus the competent but stodgy Stovebolt Six.

Then suddenly in 1954-55, American automotive technology changed. Ford launched its "Y-Block" pushrod overhead-valve V-8 in 1954, which was followed by Chevy's small-block V-8 the next year. It was a classic battle of the giants: Dearborn versus Detroit, complete with a raging horsepower race, stock-car competition drawing record crowds, and polarized loyalties. Here were the two traditional U.S. auto giants trying desperately to outdo and outsell each other.

1955 Ford Thunderbird
1955 Ford Thunderbird
Click image to enlarge

Into this total, unconditional war were plunged the Corvette and Ford's new two-place Thunderbird. By 1955, when the T-Bird arrived, the Corvette was nearly ready to receive its last rites. But also by 1955, Chevrolet and GM were enjoying the best money years of their lives. So was Ford. And thus the tremendous Ford/Chevy rivalry manifested itself on both technological and sales levels. Without GM's corporate fitness and wealth, the 'Vette would surely have joined such mid-Fifties memories as the Nash-Healey, Kaiser-Darrin, and Hudson Italia. And even Ford's moderately successful 1955-57 Thunderbird, which outsold the Corvette by more than five-to-one during those years, didn't show a profit. Money wasn't at issue, though; rather, it was corporate ego and divisional glory. Chevrolet wasn't about to let the T-Bird kick sand in its face.

As has been noted, the 1953-55 Corvettes had an odd focus. Their fiberglass bodies said high tech, and their styling showed that Harley Earl had a good understanding of the sports car mystique. But the old Stovebolt Six and the Powerglide automatic put the early 'Vette in a compromised position against true sports cars like the Jaguar XJ-120. Six-cylinder 'Vettes weren't especially quick, they leaked and squeaked, and handled like motorboats. Not to put them down, but there was ample reason not to buy a Corvette in its formative years.

And that's where Zora Arkus-Duntov comes in. Arriving at Chevrolet in May of 1953 he was born in Belgium of Russian emigre parents and educated in Germany. He'd been around the track a few times, notably with Allard in England. Just before going to Allard, he and his brother Yura designed the Ardun overhead-valve conversions for Ford's flathead V-8, which Sydney Allard used in some of his sports/racing cars. Zora was an accomplished performance engineer, a top-notch chassis designer, and a good race driver as well. Ed Cole hired him to help make all Chevrolets -- not just Corvettes -- outperform the hottest cars of the day. Zora's job was partly to create Chevy's competitive edge and partly to promote it.

Zora became the catalyst that transformed the Corvette into a genuine sports car. In the days when Cole was still Chevy's chief engineer, he and Duntov decided to abandon the boulevard approach -- leave that to the Thunderbird -- and to head for the track and run with the big dogs. Again, it was only because Chevrolet had a V-8 in the works and could afford to throw good money after bad that Cole and Duntov (and to some extent, Earl) lobbied top management to legitimize the Corvette as a competitive sports car. Cole convinced his immediate boss, Chevrolet's then-general manager Thomas Keating, that this was the way to go. Keating, Earl, and Cole then convinced GM president Harlow Curtice, which sewed up all the necessary people in high places.

It wouldn't have made much sense not to drop the V-8 into the 1955 Corvette, and indeed only six 'Vettes came through that year with the six. What didn't make sense was the Powerglide transmission, the only gearbox available until late in the model year, when the three-speed manual became available. That left most '55 'Vettes definitely unsports-car-like.

The Corvette's extensive facelift for 1956 used basically the same molds as before, yet with enough detail changes to make the 1956-57 cars unmistakably different. Styled under the careful direction of Chevrolet studio chief Clare MacKichan (pronounced MacKeekan), the 1956-57 models took minor themes from the Mercedes-Benz 300SL "gullwing," notably its thrusting headlights and twin hood bulges. The coved sidesweeps, meanwhile, came from the LaSalle II Motorama show car. New also were rounded rear fenders with inset taillights. Roll-up windows were the biggest comfort improvement in a mostly unchanged cockpit.

Zora worked on the 'Vette's handling after finding that the early cars' front and rear suspensions were fighting each other. By changing caster, steering geometry, spring angle and travel, shock rates, and rollbar sizes, Duntov had handling pretty much sorted out by 1956. "Now the car goes where it's pointed," he pronounced. The '56 Corvette was also fitted with more fade-resistant drum brakes, which it definitely needed.

That year's 265-cid V-8 ranged in power from 210 to 225 bhp (240 with an optional Duntov cam), thanks partly to new exhaust manifolding and dual-point ignition. The twin four-barrel carbs utilized progressive linkage and stood on an aluminum manifold. For 1956, too, the three-speed became standard, so Powerglide was pushed over to the options list.

Cole and Duntov realized that a sports car wouldn't get serious recognition without setting some records and winning some races, so in January 1956 Zora ran a modified 'Vette at Daytona's Flying Mile Speed Trials to a two-way average of 150.583 mph (242.34 km/h). That car used perhaps the most famous Duntov cam, a long-duration grind -- quite unsuitable for the street -- that boosted power in the 6200-7000-rpm range. John Fitch pushed another Corvette to Daytona honors by setting a 90.932 mph (146.34 km/h) standing mile record and 145.543 mph (234.23 km/h) in the production sports car category. Next up was the Sebring 12-hour race. In a production Corvette, Ray Crawford and Max Goldman finished 15th overall and first in the GT class -- not bad for a division trying hard to shed the old Stovebolt image.

The Corvette's rite of passage, its transformation from sportster to sports car, though, came that spring on the 2.1-mile road course near Pebble Beach, California. Everything went wrong before the race and, even at the starting line, the twin four-barrels flooded when dentist/driver Dick Thompson tromped the gas pedal. The engine coughed and died. Half a dozen cars roared past while Dr. Dick tried to restart. When he finally did, he took off like a shot and disappeared at the back of the pack into the Monterey pines.

Spectators could hear the cars buzzing around the track, but they couldn't see them. Finally, the racers burst into the open again and, to everyone's surprise, including his, Thompson was in the lead! The Corvette had managed to pass everyone on that first lap. Thompson stayed on top for two-thirds of the race, until his stock drum brakes overheated, whereupon a factory-backed Mercedes gullwing passed him and eventually won. Dr. Dick finished second, and first in class. Notably, Thompson became the Sports Car Club of America (SCCA) C-Production class champ driving Corvettes in 1956 and B-Production champ in 1957. Corvettes were to retain the B title for the next seven seasons.

It was that day at Pebble Beach, according to Barney Clark, Corvette's longtime ad copywriter, that the fiberglass flyer finally turned the comer. From there on it was mostly easier for America's only sports car to be accepted by purists and the public alike.

1957 Corvette
1957 Corvette
Click image to enlarge

There were no visual changes for 1957, but the V-8 grew to 283 cubes and a four-speed manual became available that May for $188. Horsepower started at 220 with a four-barrel carb and escalated to 245 and 270 with twin quads. With the new $481 Ramjet fuel injection the ratings were 250 and 283 bhp (hydraulic lifters with 250; solids with 283). The latter achieved the magic "1 h.p. per cu. in.," as Chevy ads blared out. GM's Rochester Division supplied the '57 Corvette's mechanical continuous-flow injection system, development of which involved Duntov, John Doiza, and Rochester. Ed Cole approved of the system, but Charles F. Kettering -- inventor of the 1912 Cadillac's electric self-starter and later chief of research at GM -- didn't much like the complex, cantankerous system. In fact, he once commented that if Rochester's fuel injection had been around for a long time and someone had come up with a brand-new invention called the carburetor, he'd jump at it.

One important option for 1957 was the competition suspension package, RPO 684, which listed at a towering $725. This included heavy-duty springs, shocks, and rollbars, 16.3:1 quick-ratio steering, Positraction differential with a variety of available axle ratios, brake cooling mods, and Cerametalix linings. This plus fuel injection plus the new four-speed made even a showroom-stock Corvette extremely competitive on any race course.

No review of the 1956-57 Corvettes would be complete without a mention of that era's two special competition models: the SR-2 and the Sebring SS or Super Sport. Both were created to compete at the 12 Hours of Sebring, in which the SR-2 did better than the SS. Actually, two SR-2s were built: handcrafted, race-prepared versions of the stock Corvette. The first was built specifically for Harley Earl's son, Jerry, in March 1956. It ran on the beach at Daytona, setting a standing-mile mark of 93.047 mph in the modified class and turning 152.866 mph in the flying mile. This car also ran the '57 Sebring race where it placed 16th.

A second SR-2, essentially a retrimmed stock '57 Corvette, was built for GM president Harlow Curtice. This car had a lower, sharper fin than the original SR-2 and wasn't raced. Although the Jerry Earl car survives, what became of the of the Curtice SR-2? It is alive and well in Michigan and can be seen at the Corvette Museum and is getting ready for the Motorama Cruise to the N.C.M. (This information came from Robert Willis who wrote me on Jan. 7, 2002.)

The bizarre story of the Sebring SS could fill volumes. It came about when Harley Earl got his hands on the ex-Sweikert/Ensley D-Type Jaguar that had placed third in the 1956 Sebring race. The Jag arrived minus an engine, which suited Earl because he wanted to put an injected Corvette V-8 in it. He also wanted to disguise the body so he could run it in the '57 Sebring.

Duntov, on vacation at the time, got wind of Earl's plan, flew back to Detroit, and talked Harley into letting Chevrolet build a tube-frame Corvette for him instead of the Jaguar-based car. Earl acquiesced (he might have had Duntov's alternative in mind all along), and the resulting car became known as the Corvette Sebring SS. It looked great, but was dogged by insufficient testing time, lack of driver confidence, and inordinate bad luck. The SS lasted 23 laps into the 1957 race and went out with a crushed suspension bushing.

1956 Sebring Racer
1956 Sebring Racer
Click image to enlarge

The Sebring SS misadventure was especially disheartening because, had this car won Sebring, Duntov would have gone on to Le Mans with it, and the SS might have changed the course of racing history vis-a-vis Ford's later efforts with the GT-40, Cobra, and others. General Motors currently owns the Sebring SS, which it trots out from time to time for shows and Corvette club events.

These two special racing cars, while not successful in themselves, did lead to bigger and better things, particularly for production 'Vettes. They proved to be living, fire-breathing improvers of the breed. And as the breed improved and more people became aware of the Corvette's potential, sales increased, going from 700 in 1955 to 3467 in 1956, and to 6339 for 1957. The car still wasn't making money for Chevrolet, but that, too, would come in time. Meanwhile, Chevrolet's 'glass slipper proved an asset whose value, as they say, couldn't be measured in mere money.

Motor Era Blog

Auto Service Repair Manuals on Motor Era