My 1958 Pontiac Bonneville Convertible

1958 Produced 3,906 Bonneville Convertibles - 9,144 2-Door Coupes and a total of 217,303 Total Pontiacs.

1958 Pontiac Bonneville Convertible

1958 Pontiac Bonneville Convertible

If Harley Earl could somehow walk into Ken’s garage he would be pleased to see on display one of the 3,096 Pontiac Bonneville Convertibles that rolled off the production line the year he retired from GM.  No doubt he would be proud of the sub culture of collectors, owners, admires and restorers like Ken who preserve the Pontiac legacy.  One of the longtime GM styling chief’s last designs; the ’58 body style was only made for one year. Sparkling with chrome trim and finished in spectacular Graystone White with Copper Accent highlighting the dramatic side spear, Ken’s 1958 Bonneville is a fitting tribute to its designer. This highly optioned matching numbers car boasts power steering, power brakes, power windows, speckled woven floor carpet, leather interior, power rear antenna, rear seat speaker, dual exhaust, E-Z Eye Glass, fender skirts and the rare Sportable Transistor Radio. The original 370 Cu In V-8 fitted with the three duce (Tri-Power) carburetor set up puts out 300 horsepower and is bolted to a four speed Strato-Flight Hydramatic transmission.

Undoubtedly one of the flashiest of all of the 1950's vehicles Bonneville’s dazzled customers with lavish amounts of chrome and unique two-tone exterior color combinations. Deluxe interiors showcased all 58 models. The Bonneville also featured wraparound windshields and long striking “rocket”-like” sidespears plus chrome hash marks on the front fenders. They were bold looking with their shrouded four-headlight front end, lower stance and concave-shaped rear quarter panels.

When the racy looking `58 Bonneville was fitted with Tri-Power carburetion, it made for a very fast and desirable cruiser. Perhaps that was the reason a Tri-Power `58 Bonneville was chosen to pace the Indy 500 that year.  Today, finding a 1958 Bonneville convertible or any `58 Pontiac for that matter, to restore is quite difficult as there aren't that many around. Owners of these distinctive-looking 1950s icons rarely part with them, no doubt thanks in part to the car's quality construction, wild looks and powerful V-8.

As Pontiac enthusiasts have long known, the heart of every V-8-powered Pontiac is its engine. These big-bore powerplants are engineering masterpieces, and are considered by many professional engine builders to be the very best carbureted V-8 engines that General Motors ever produced.  The stout blocks were overbuilt with unusually thick webbing, strong bulkheads surrounding the main bearings and thick cylinder walls. The crankshafts were tough forged steel and if that wasn't enough, a windage tray was standard. The windage tray, which was fastened atop the crankshaft's main caps, scrapes the oil off the crankshaft as it spins, reducing the oil's parasitic drag and freeing up a few horsepower.

In a day where nameless legions of designers sit in front of computers and spew out shapes like bland porridge painted in drab lifeless colors the names Earl, Knudsen & DeLorean are reminders of a Pontiac past when style stirred the emotions and powerful engines satisfied the need for speed and adventure.   In a time when you could name cars just by their shape, they were the rock stars of the auto world who gave us milestone cars like the Bonneville that would set the standard for style and performance for the next two decades.

By September of 2008 GM’s problems were exacerbated due to the financial crisis brought on by the sub prime home mortgage debacle.  After 107 remarkable years, Pontiac became a causality of restructuring when GM announced on April 27, 2009 that the brand would be discontinued. On June 1, 2009 GM was forced to file for Bankruptcy.  In exchange for government loans the U.S. took a 60 percent stake in the company and it essentially became “Government Motors”. 

According to The Detroit News, there were no festivities to mark the end of the brand when the last U.S. built Pontiac, a white G6 sedan, rolled off the assembly line in Orion Township, MI. on Wednesday November 25th 2009.  Final dealer franchises expired October 31, 2010.

Production Figures

Total Pontiac Production for 1958


Custom Bonneville Convertibles



1958 Pontiac Bonneville Convertible

Matching Numbers!
Cost With Factory Options: $5712.30
Graystone White with Copper Accent Acrylic Lacquer Paint
370 Cubic Inch V-8 - 300 Horse Power
3-2 Barrel Rockchester Carbs
Compression 10:1
Hydramatic Transmission
122" Wheel Base
3.97:1 First Gear Ratio
3.23:1 Rear Axle


Power Windows
Vanity Mirror
Power Brakes
Rear Speaker
Leather Interior
Courtesy Lights
Speckled Woven Floor Carpet
Electric Clock
Trunk Light
Dual Exhaust
Under Hood Light
Backup Lights
Electronic Antenna
Rear View Mirror - Non Glare
Power Convertible Top
EZ Eye Windshield
Wonderbar Radio
Fender Skirts
Sportable Tranistor Radio