1968 Chevrolet Corvette Development
GM design chief Bill Mitchell and company had just the thing to make their baby, the 1968 Chevrolet Corvette, considerably more exotic at the relatively low price of a new fiberglass body. It was the Mako Shark II, one of the most famous show cars of all time.
The 1968 Chevrolet Corvette's contours were
softer than those of its inspiration, the Mako
Shark II show car.
The Motoramas were a thing of the past by the mid-Sixties, but GM was still gauging public reaction to its near-term models by displaying them as slightly exaggerated "concept cars." The Mako II was quickly recognized for what it was: a trial balloon for the next-generation Corvette. As if to support that view, the original nonrunning Mako II mock-up was retired during 1965 and replaced on the show circuit by a fully operational version. Completed in October of that year, this second Mako II was less radical than the first and thus -- tantalizingly -- more producible. The ever-busy Corvette rumor mill went into overdrive.
Executed under Mitchell's direction by young Larry Shinoda, the Mako II had been initiated in early 1964, more than a year before the first show model appeared. Although adaptable to either front- or rear-engine positioning, its basic design became the take-off point for a new front-engine "theme car" as an alternative to the more radical mid-engine shapes that had been proposed. Once the midships format was abandoned for good, the Shinoda/Mitchell car was sent to Chevrolet Styling under David Holls, where Henry Haga's studio adapted it for production on the existing Sting Ray chassis.
The result was much like the Mako II from the beltline down except for softer, less extreme contours. The one major change on the way to production involved the show car's "boattail" roof. Although retained for the first production prototype, this quickly gave way to a tunneled treatment adapted from the design a Duntov-led group had worked up when the mid-engine concept was still alive.
Chevy may simply have been seeking a different look or perhaps better rearward vision than in the Sting Ray fast-back. In any case, it was intended from the beginning that the vertical back-light -- as well as that portion of the roof above the seats -- be removable. Though the traditional Corvette convertible would continue. Chevy felt this new coupe configuration -- really a semiconvertible -- would appeal just as much to the open-air crowd while offering the better weather protection and structural rigidity associated with closed bodies. Porsche's 911/912 Targa convertible reflected similar thinking.
Unfortunately for Holls, Haga, and Duntov, the Mako II's basic shape proved problematic, and the production styling job didn't go as smoothly or as quickly as expected. For one thing, the new design turned out to have excessive front-end lift at high speed, which seriously compromised stability. A rear spoiler was added to help keep the tail down, but this only lifted the nose more.
Duntov had experienced something similar with the Sting Ray, and he was determined to lick the problem before production started. Additional wind tunnel work produced functional front-fender louvers that relieved pressure buildup within the engine compartment at speed, and also yielded a small "chin" spoiler below the grille to direct air around the car instead of beneath it.
The Targa-style roof also proved thorny. Its removable section had been conceived as a single piece of fiberglass, but production engineers found that the resulting body/frame combination wasn't stiff enough in torsion to prevent creaks and groans. Accordingly, they added a longitudinal support bar between the windshield header and the roof's fixed rear "hoop" section, thus creating the first T-roof. This solution came so late that it didn't appear in some early publicity photos of the new coupe. The Sting Ray name did appear on those pictures, though not on the car itself, another last-minute change.
The most serious deficit of the Mako-inspired styling was poor engine cooling, especially with the big-block mills carried over from the Sting Ray. With the new design's narrow engine bay and shallow grille, radiator air flow was found to be marginal in hot weather, especially with the air conditioning on. That didn't bode well for the annual long-lead press meeting in July 1967, so Duntov hastily cut two oblong slots into the body just above the front spoiler and made the spoiler deeper so as to force cooling air through them. That did the trick: The prototype, with its Mark IV 427-cid engine, kept its cool on the 85-degree press day, so the slots were ordered for production and the grille was blanked off, since it contributed little or nothing. Still, cooling problems would dog the fifth generation right to the end.
One Mako II feature that survived to production virtually intact was a vacuum operated flip-up panel concealing the windshield wipers. It was a great idea for a show car, flashy and futuristic, but something less than wonderful for a real-world car that had to contend with ice and snow. A good deal of development time was spent making it work, but the final product was none too reliable.
Hidden headlamps were continued but were now simple flip-up jobs rather than the Sting Ray's rotating assemblies; they also operated via engine vacuum, versus the previous electric motors. An external trunklid was still conspicuously absent from both body styles, but the convertible retained Corvette's traditional rear-hinged top cover, and an accessory hardtop was designed to match the new Shark styling.
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