The name Bonneville has been synonymous with automotive performance since nearly the advent of the motorized carriage itself. The first land speed record events were held at the massive dry lake bed, along I-80 located near the Utah-Nevada border all the way back in 1914. In the years since, the 46-square-mile expanses of the densely-packed salt pan have hosted all manner of high-performance contests and testing. Few locations in the world carry a moniker as apropos for a vehicle with a focus on straight-line thrust.
Determined to steer General Motors in a more youthful, performance-oriented direction, designer Harley Earl went to the source for inspiration — the enthusiasts. Designed by Earl, and named after a trip to the Salt Flats, the Bonneville Special was the Pontiac division’s theoretical answer to the Corvette. The car was outfitted with a Plexiglas canopy with gullwing sides and a fiberglass body. Motivation came from a high-output version of Pontiac’s 268ci inline-eight powerplant, which the company dubbed the “Special-8.” | GM photo
GM first attached the name to one of their automobiles in 1954, when they debuted the Bonneville Special concept at the Motorama show at the New York City’s Waldorf Astoria. Designer Harley J. Earl had been inspired by a recent trip to the Salt Flats to check out the speed trials, and he was keen to find new ways to frame Pontiac as GM’s premiere high-performance brand.
While the concept car shared much of its underpinnings with the two-seater Corvette, the vehicle that would actually go into production in 1958 was a different animal entirely. The Bonneville helped establish the muscle car formula that Pontiac would use to great effect just a few years down the road with the GTO: Build a coupe that could be optioned with minimal frills, stuff the most potent engine your company builds into the engine bay, and offer it at a price that folks can afford.
In 1957 the Bonneville name had been used as a trim package for the Star Chief called the Star Chief Custom Bonneville. But the Star Chief Custom Bonneville was loaded with features as standard and carried a hefty price tag as a result. When the Bonneville became its own model the following year, that strategy changed. Although the car could be lavishly appointed if customers saw fit, most of the luxury content was now optional, thus allowing enthusiasts to spec out a machine that was high on horsepower and low on frills. | Barrett-Jackson photos
The result was the 1958 Pontiac Bonneville. Produced to celebrate both GM’s 50th anniversary and Earl’s forthcoming retirement, the Bonneville was based on the luxury-focused Star Chief (which itself was a derivative of Chevrolet’s 210/Bel Air coupe), but its more performance-focused design would help put the Pontiac brand on enthusiasts’ radar in the late 50s. While the vehicles that the nameplate was attached to would change dramatically over the subsequent decades, the original Bonneville spawned a production legacy that spanned nearly half a century across ten different generations.
Development and Specifications
For the 1958 model year, General Motors introduced new bodies and chassis for all of its passenger cars, and this major shake-up of the model portfolio gave Pontiac some room to reposition the brand with a more sporting, youthful vibe. The Bonneville went from being a trim package on the Star Chief the previous year to its own stand-alone model. Positioned as a direct response to Chrysler’s letter-series Chrysler 300 and the DeSoto Golden Adventurer – two Mopar models which were built on a similar concept of placing high performance near the top of the list of priorities – the Bonneville scored the high-performance powerplants of the Star Chief, but it rode on the shorter, 122-inch wheelbase of the Chieftan. While the Chieftan wasn’t exactly svelte, this shorter wheelbase provided a tangible performance advantage over the larger Star Chief chassis.
Sitting at the top of the engine totem pole for the ’58 Bonneville was this 370ci overhead-valve V8, which was outfitted with a Rochester fuel-injection system derived from the one introduced for the Corvette in 1957. While it was considered cutting-edge technology at the time, the injection system’s finicky reputation and high price tag pushed most buyers toward the mid-range engine option, which utilized a triple two-barrel carburetor setup. The Tri-Power engine might have been down ten horsepower versus the Fuelie from the showroom, but most enthusiasts were more comfortable tuning on this more-familiar hardware. | Barrett-Jackson photo
At the same time, engine design was evolving at a rapid pace. Pontiac had put their straight-six and straight-eight powerplants out to pasture at the end of 1954 to make room for a new overhead-valve V8 design that shared its core architecture with Chevrolet’s new small-block. Over the next few years, the displacement numbers would increase, along with the horsepower. By the time the engine found its way into the new Bonneville, it had ballooned to 370 cubic inches. Depending on the options selected, that mill’s output ranged from 255 horsepower all the way up to 310 ponies, the latter outfitted with GM’s new Rochester fuel-injection system that had debuted on the Corvette “Fuelie” the year prior.
Because of the fuel-injection system’s high price tag and reputation for temperamental behavior, most Bonneville buyers opted for the trio of two-barrel carburetors offered in the Tri-Power setup, which dropped the horsepower to an even 300 but offered better tunability and a more attractive bottom line.
Although a column-shifted, three-speed manual was the standard gearbox on the Bonneville, few buyers settled for it. Most instead, sprung the extra coin to get GM’s four-speed, Strato-Flight Hydra-Matic automatic, which featured a low 3.97:1 first-gear ratio for the better pull from a standstill. Also giving the big Bonneville some extra punch out of the hole was the availability of the Safe-T-Track limited-slip differential, which debuted in 1958 as well.
The '58 Bonneville was by no means a small vehicle, but riding on a two-inch shorter wheelbase than the Star Chief lent some credence to the notion that the car would be a better performer out on the street. Images: RM Auctions
The Bonneville’s suspension setup consisted of unequal length A-arms and shocks with coil springs up front, and coil springs also made their way to the rear in lieu of the leaf springs that Pontiac normally outfitted its cars with. An Ever-Level air suspension was also on the options list. Drum brakes were installed at all four corners as standard, measuring 12 inches in diameter up front and 11 at the rear.
Two body styles were offered for 1958 – Sport Coupe and Convertible. Hemmings reports that Pontiac would end up selling 12,240 Bonnevilles in total that year, with 9,144 customers opting for the coupe, while the remaining 3096 buyers chose the drop top.
The Strategy ChangesWith the debut of the second-generation Bonneville in 1959, the model lineup grew to five distinct configurations – coupe, convertible, four-door sedan, four-door hard top, and a wagon. The car’s appearance was a dramatic departure from its predecessor, not only due to a deliberate move away from the rocket-inspired aesthetic of the 1950s toward a more streamlined look that would typify early 1960s vehicle design, but also because of Pontiac engineer’s decision to push the wheels further out toward the fenders to create what would become known as the Pontiac Wide Track design.
While the '58 Bonneville had a clear nod to performance in its design, that quickly began to disappear as subsequent generations were introduced. By the time the fifth generation car debuted in 1971 (right), the Bonneville’s design had little to do with the original model’s intention. | Wiki Commons and GM photos
While the Bonneville continued to evolve as the 1960s progressed, intermediate-bodied cars like the GTO became the models synonymous with street performance. As a result, the larger Bonneville began to take on a more luxury-focused role in the Pontiac lineup.
By the early 1970s, the model’s connection to high performance was largely in name only, as Pontiac’s focus for the Bonneville became more specifically aimed at personal luxury.
The 80s and 90s were not particularly kind to the Bonneville nameplate, which saw the model jump to the G-Body platform before moving over to the front-wheel drive H-body platform shared by the Cadillac Seville and Buick LeSabre. Though it would remain a front-wheel drive car for the rest of its days, the introduction of the GXP model in 2004 brought V8 power back to the menu, allowing the Bonneville to go out on a high(er) note. Image: GM
The model regained some of its performance credibility decades later with the addition of the 3.8-liter Eaton M90-supercharged L67 V6 to the engine lineup, which was good for 240 horsepower by 1996, and later with the addition of a 4.6-liter, 275 horsepower V8 to the options list, which had been plucked from the Cadillac parts bin for the debut of Bonneville GXP in 2004. However, the GXP’s production would prove to be short lived, as Pontiac would discontinue the Bonneville model entirely just a year later.
Ultimately, it’s the first-year cars that would endure in the hearts and minds of performance enthusiasts. Due to the car’s significance and scarcity, the 1958 Bonneville is now a highly-sought-after commodity in the collector car market. Well sorted examples can usually be had for around $50,000, though some Bonnevilles have commanded sums well into six-figure territory at auction.
Article courtesy of Street Muscle Magazine, written by Bradley Iger.