1964 Pontiac Bonneville Convertible Plays Gigantic V8 Trick, Stays Cool With the Top Down

The illustrious nameplate – a mere option on the Tempest Le Mans in 1964 – made a clever move and borrowed the engine from the full-size Bonneville to spark the mid-size body to the ‘muscle car’ level. However, the big Poncho didn’t mind this family affair and soldiered on until 2005, far longer than the flashy GTO.

The Bonneville made its motoring debut twice, we might say – first as a concept car in 1954, strikingly similar to the Corvette, then in 1957, as a performance option for the Star Chief. Like many other Detroit legends, the Bonneville started out as a sidekick for a model. But, unlike most others, the Bonneville entered production as the absolute best option money could buy on the base model.

In ’57, the Star Chief could be optioned with the Bonneville trim, which offered a convertible body filled with every single option available in the book AS STANDARD. Only 630 were built – all fuel-injected and priced more than a base Cadillac Series 62. In 1958, the Bonneville was allowed to be a separate model and lost its glamorous twinkle of standard lavishness. The goodies were still there but offered at extra cost, and critically, they could be installed individually rather than all at once.

The production figures kept growing from one year to another, averaging 100,000 units per year in the sixties and lending a helping hand in the division’s efforts to maintain its third place in sales on the domestic market. Four body styles were available: a station wagon, a two-door convertible, and two hardtops (two- and four-door).

In 1964, the nameplate rolled out 120,259 units – 22,016 of them with a retractable roof. Between its debut in 1958 and 1965 – when the model scored 135,000 units - the convertible option constantly oscillated around the 20k-unit mark. Ironically, when the car peaked in customers’ preferences, the drop-top began losing its luster.

With relatively high production numbers, a convertible Bonneville should be a regular appearance at events and shows, and yet they seem to be hiding pretty hard. One example has come out of its den for a video shoot last fall. Lou Costabile was fortunate to get one in front of his camera, and here it is for us now.

The 1964 we’re seeing here has a nice story – the current owner bought it in 2015 from a friend who didn’t get along well with the classic Poncho. The previous owner received the splendid red ragtop as a birthday present from his son. The former caretaker of this Bonneville was very fond of the make and model since his first car had been a ’64 convertible. Unfortunately, between 2000, when he got the car, and 2015, when he sold it, he only drove it four times – and every time, something happened that ruined the fun.

After the car was bought by John Valene (the proud owner smiling for the camera in the video below), it received a replacement motor. We don’t know if this classic came out of the assembly line with the standard 389 cubic-inch eight-cylinder (6.4-liter) or the optional 421 V8 (6.9-liter), but now it sports the granddaddy of all Pontiac engines.

The torque monster 455 cubic-inch V8 (7.5-liter) now growls inside the engine's enormous bay under the hood that could serve as a landing deck for an aircraft carrier. Equally generous in real estate, the trunk could accommodate a basketball team (subs and coach included). The car comes with an automatic transmission, and the 34,365 miles (55,293 km) on the odometer don’t reflect the actual road experience on the vehicle but rather the engine mileage.

When Mr. Valene installed the big motor, the plant had 27,000 miles on it (some 43,400 km); also, the neat looks of the big convertible are the result of a repaint. Something that’s come to be very appreciated by the owner’s wife, who insisted he didn’t sell the car. (Madam, hats off to you, in the name of all the wrench-turning, gasoline-addict society!)

One of the rare factory options installed on the convertibles back in the day is the air conditioning (a hefty $430 creature comfort item). The cool factor (pun intended) is kicked up one notch by the temperature setting indicator (see it in the video at the 11:45 mark). We don’t know what happened to the original engine, nor does the owner mention what specific 455 is in this Bonneville now. The A/C option tells us that the rear gearing is at least a 2.69:1, as no numerically lower rear was offered that year on the full-size Pontiacs equipped with the expensive add-on.