1958 Pontiac Bonneville Series 25 Custom Sport Coupe

Pontiac retired both its six- and straight-eight-cylinder engines at the end of the 1954 model year. For 1955, all the Pontiacs were powered by V-8 overhead-valve engines. Mid-year, a $35 Power Pack option added a four-barrel Rochester carburetor, which brought horsepower to 200 BHP on Hydra-Matic cars. The displacement grew to 317 cubic-inches for 1956 and a dual four-barrel carburetor option boosted power to 285 brake horsepower. Approximately 200 cars were fitted with this option. Another increase in displacement was observed for 1957. A special Bonneville Convertible that used Rochester fuel injection was released in the Star Chief line. The engine was rated at 315 horsepower and just 630 were built. The most powerful engine option was a NASCAR Tri-Power option with three 2-barrel carburetors.

For 1958, General Motors introduced new bodies and chassis for all cars. The Bonneville was made its own separate series consisting of a convertible and a hardtop coupe. The standard engine was a 285 brake horsepower four-barrel V8, with the fuel injection and Tri-Power still available as optional equipment. Only a few customers requested the fuel injection. The Tri-Power cars came with three Rochester two-barrel carburetors, 10.5:1 compression, and a high-lift camshaft.

This particular example is a Super Deluxe Sport Coupe that was been given a restoration. It is equipped with the Tri-Power option and the Strato Flite four-speed Hydra-Matic transmission. The car is equipped with power steering, power brakes, and power windows. The car is also fitted with a Trans-Portable radio that was introduced for 1958. The radio can be removed from the car and used as a portable unit. The car is also equipped with a rear antenna and rear speaker. There is a tissue dispenser, rear fender skirts, and door edge guards.

The car is painted two-tone green with an interior of similar hues of green, with the seats upholstered in a vinyl-cloth combination.

The car has four-wheel hydraulic power drum brakes, a four-speed Hydra-Matic automatic transmission, and a 370 cubic-inch overhead valve V8 engine rated at 300 bhp.

By Daniel Vaughan | May 2015