Hooniverse Obscure Muscle Car Garage – The 1957 Pontiac Bonneville


Welcome to the Hooniverse Obscure Muscle Car Garage, a regular feature which aims to expand the notion of what a muscle car is, and maybe, have some fun in the process. Pontiac wasn’t always known as the excitement division; by the early 50′s it had earned a reputation of appealing to older drivers, with plodding engines and unexciting styling. The turning point came in the fall of 1956 with the introduction of Pontiac’s first performance car: the fuel-injected, limited-edition Pontiac Bonneville.


Semon E. “Bunkie” Knudsen, at the age of 44, became the youngest general manager of a car division at General Motors on July of 1956. This tired GM division needed some excitement, and there were two areas that could be exploited to bring a more youthful feel to Pontiac: styling and performance. The process of designing and tooling up to produce an all-new car takes time, but introducing performance offered more immediate opportunities. Therefore, in about half a year into his tenure as division chief, Bunkie Knudsen was able to put the fuel-injected Bonneville convertible on the road.


The basis for the new model was the latest version of the Pontiac V8. Introduced at 287 cubic inches and 180 horsepower in 1955, displacement was increased to 317 cid for ’56, then to 347 cubes inches thanks to a longer stroke. The ’57 Pontiac engine was available in five levels of tune that made from 227 to 290 horsepower at the wheels, plus a special version with mechanical valve lifters and three two-barrel carburetors, producing 317 HP.


The Bonneville had its own version of the 347 CID engine, with something new: fuel injection. Its injection system was a mechanical continuous-flow type that directed fuel to each intake port. Conceived by GM Engineering, the unit was manufactured by Rochester Products. The setup was similar to the fuel-injection system used in 1957 Chevrolets and Corvettes. However, manifold designs and fuel-meter locations differed between the two makes. At 10.25:1, the compression ratio of the Bonneville engine was a quarter-point higher than the triple-carb engine available in other Pontiac models.


The powerplant made 310 bhp at 4,800 rpm and a healthy 400 pound-feet of torque at 3,400 rpm. The Bonneville was available only with the Hydra-Matic automatic transmission. Motor Trend Magazine tested the new car, and found that at 8.1 seconds, the new Fuel Injected Pontiac was just one-tenth of a second quicker to 60 mph than another Pontiac with the 290-horsepower triple-carb engine, and it was more than a second slower in the quarter mile. However, the Bonneville makes a well-equipped convertible, and was Pontiac’s heaviest ’57 model at 4,285 pounds.


Styling for the 1957 Pontiacs represented a second facelift of the design that was introduced for ’55. All series featured rocket-silhouette side trim that ran the full length of the car–and provided an obvious site for two-tone paint applications. The “Silver Streak” chrome bands on the hood that graced almost every previous Pontiac were removed for good. The Bonneville took its name from the vast, stark, and legendary 100-square-mile section of salt flats in northeastern Utah where land-speed records are set. Pontiac had first applied the name to a 1954 show car, the two-seat Bonneville Special, which featured a fiberglass body and a Plexiglas “bubble-top.”


The 1957 Bonneville shared the Star Chief’s 124-inch-wheelbase chassis. Front-fender hash marks and a ribbed panel on each rear-quarter panel were other exclusive touches. “Fuel-Injection” badges on the front fenders announced the car’s special engine. Other standard equipment included power steering and brakes, power windows, an eight-way power seat adjuster, leather upholstery, a Wonderbar radio with electric antenna, padded dashboard, electric clock, tri-blade wheel covers, and whitewall tires. The price for a Bonneville came to $5782-a good $2677 more than a Star Chief Custom Convertible. Only 630 were built.


Rare as it was, this ride marked the beginning of the Pontiac performance legacy: it was the first fuel-injected Pontiac, and with horsepower conservatively estimated at 310 it was powerful for the time. So what do you think: does it qualify as an Obscure Muscle Car? Can a full-size 50′s convertible realistically be considered as such? Comments are always welcome, so let me know what you think.


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Please Note: All Images are screen grabs from around the web. If you want credit for any image, please let me know in the comments section. Thank You!

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