A hardtop joined the Bonneville convertible for 1958, and shared a one-year-only design with other Pontiacs.

©2007 Publications International, Ltd.

1958 Pontiac Bonneville

Hopes were high for the 1958 Pontiac Bonneville, and Motor Life predicted that “Pontiac [will have] the necessary appeal to win back some of the sales [it] lost last year.” The changes were indeed major. No longer billed as limited-production, the Bonneville convertible gained a hardtop Sport Coupe running mate to become a separate, top-line series. Moreover, all 1958 Pontiacs were new from the ground up, with completely restyled bodyshells on a Cadillac-inspired cruciform (X-member) frame.

Greater rigidity was claimed for the new backbone, which Pontiac would retain through 1960, and it facilitated the use of coils instead of semi-elliptic leaf springs at the rear for a better ride. (It also afforded precious little protection in a side impact.)

Wheelbases and the twin-A-arm/coil-spring front suspension stayed the same, but Bonneville was put on the shorter Chieftain platform in the interest of better handling. Though trim remained top grade, most of the 1957 Bonneville’s lavish equipment now appeared on the option sheet, cutting 1958 base price by some $2,300.

The year’s most fascinating new feature was optional “Ever-Level” air suspension, modeled after Cadillac’s system on the 1957 Eldorado Brougham and offered across the board at $175. However, orders were few at that price, and the setup proved so troublesome that Pontiac gave up on it after only a year, about as quickly as other makes gave up on their equally problem-plagued systems.

With performance a major thrust, all 1958 Pontiacs got the 370 V-8, now called “Tempest” and offered in six different versions. Most Bonnevilles packed the single-four-barrel unit, with 10:1 compression and 285 horsepower with Hydra-Matic.

Fuel injection was still available -- and still troublesome -- and a formidable $500 asking price discouraged all but 400 buyers before the system was canned during the year. So the 300-horsepower Tri-Power engine remained the darling of the leadfoot crowd -- and a performance bargain at just $93.50.

Styling of the 1958 Bonneville was more like that of lesser Pontiacs and not bad for the day, but not up to its 'New Direction' label.

©2007 Publications International, Ltd.

Motor Trend timed one at a creditable 8.2 seconds in the 0-60 mph sprint and 18.8 seconds at 88 mph in the standing quarter-mile. Mechanix lllustrated’s Tom McCahill hit 125 mph with a 285-horsepower car, moving him to exclaim: “The 1958 Pontiacs are hotter than a blowtorch.”

They should have been slower: four inches longer, two inches wider, and some 100-200 pounds heavier than the 1957s. This was dictated in part by the “New Direction” styling, which still wasn’t the best -- though it could have been much worse. Yet even the Bonneville, the most sparkling of the line, doesn’t look too bad now next to some other 1958s, notably Buick, Oldsmobile, and Mercury.

Being more readily available, the 1958 Bonneville sold much better than the 1957, with 9,144 hardtops and 3,096 convertibles. But it was scant consolation in a year when most everybody except AMC’s Rambler was down -- way down. While Chevrolet sales were off by 17.5 percent and Oldsmobile’s by 20 percent, Pontiac dropped more than a third.

Yet the Bonneville proved Knudsen knew what he was doing. “There was no point competing against Chevrolet,” he said later. “They had their market sewn up tight. But setting out after Buick and Oldsmobile was possible.”

Like other General Motors divisions that year, the 1958 Pontiac was a one-year-only design, because the company had decided to share bodies more closely from 1959 on. But in line with his plan of moving Pontiac upmarket, Knudsen managed to exchange Chevrolet’s forthcoming A-body for the larger, equally new Buick/Oldsmobile B-body.

“Up until then,” he observed, “Pontiac had used the Chevrolet body, maybe with an extended rear deck. There was no point in that, and I think the results bear out our decision.”

For more on the 1959 Pontiac Bonneville, continue to the next page.

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