Arizona

16-17 January 2014

Lot 80

1958 Pontiac Bonneville 'Tri-Power' Convertible

To be auctioned on Friday, January 17, 2014

Sold for $99,000

  • Chassis no. P558H1045



300 bhp, 370 cu. in. OHV V-8, triple two-barrel Rochester carburetors with vacuum linkage, Strato-Flight four-speed Hydra-Matic automatic transmission, independent front suspension with unequal length A-arms and coil springs, live rear axle with coil springs, and four-wheel power drum brakes. Wheelbase: 122 in.

  • AACA Senior National First Prize winner
  • Desirable 300-horsepower Tri-Power engine
  • An outstanding highway cruiser


You don’t have to know anything about a ’58 Bonneville Convertible to appreciate it. It is a car that could only have come from America; it was 211 inches and 4,040 pounds of steel and chrome, and it had all of the hot engine options you could ever want. In its first year of having its own line of cars, Bonneville was among the hottest cars in the red-hot GM lineup, and a Tri-Power Bonneville Convertible paced the 1958 Indianapolis 500. It was an expensive and exclusive car, though—both price and production were comparable to Corvette—and only 3,096 convertibles sold that first year.



Beyond the styling, Pontiac was a high-performance engine company with its own unique offerings. The 370-cubic inch V-8 was overbuilt, dependable, and supremely powerful, especially with the Tri-Power/Hydra-Matic transmission combination, which yielded 300 horsepower, thanks to 10.5:1 compression and a high-lift cam. Hot Rod tested a Tri-Power sedan in 1958, and they found that it was capable of 60 mph in 7.6 seconds, but the convertible does weighs about 200 pounds more than the sedan, so it would be a second or two slower. (As few enthusiasts today are buying Bonnevilles to win drag races, it’s an easy trade-off to make for convertible style.) A Rochester fuel-injection setup that was rated at 310 horsepower was also available, but in testing, Motor Trend found that the Tri-Power was actually faster and, of course, much less trouble.



Restorations of 1958 Bonneville Convertibles are difficult and expensive, as supplies of NOS parts and parts cars are both highly limited. Fortunately, this car has not only had an amazingly well-preserved restoration, but the consignor has also ensured that it is in top running condition. The carburetors are freshly tuned, and a new top and wide whitewall radial tires complement the interior work, which includes new color-keyed belts. A recent all-day rally has demonstrated the car’s ability to run at freeway speeds without difficulty. In fact, this car would not be available if the consignor did not think it was too nice to be exposed to the salt air of his beachfront home.



Any fan of the Bonneville Convertible knows that Tri-Power ’58s seldom trade hands. Finding one ready to drive or show, with all needs attended to, is an annual event at best.

Please contact our exclusive automotive transportation partner, Reliable Carriers, for a shipping quote or any other information on the transport of this vehicle.

Alain Squindo


Detroit, Michigan

Alain Squindo joined RM Sotheby's in 2007, after graduating from Georgetown University in Washington, D.C., with a degree in Histo... read more

Alex Classick

aclassick@rmauctions.com

+44 (0) 20 7851 7070
United Kingdom

Alex Classick joined RM Europe in 2011 as a car specialist, after graduating from Nottingham University with a degree in Business Mana... read more

Alexander Weaver

aweaver@rmauctions.com

+1 310 559 4575
California, United States

Alexander Weaver joined RM Sotheby's in 2011 as a car specialist, after graduating from Furman University in South Carolina. Born ... read more

Annette Abaci

aabaci@rmauctions.com

+49 (0) 40 441 95 737
Germany

With post-secondary degrees in Economic Science and Mechanical Engineering, Annette Abaci initially worked part-time at Mercedes-Benz ... read more

Augustin Sabatié-Garat

asabatie-garat@rmauctions.com

+44 (0) 20 7851 7070
United Kingdom

Augustin Sabatié-Garat joined RM Europe in 2012 as a senior car specialist, after more than a decade in the collector car hobby... read more

Barney Ruprecht

BRuprecht@rmauctions.com

+1 519 352 4575
Ontario, Canada

Barney Ruprecht graduated from Boston University in 2013 with a degree in Hospitality Administration. In ... read more

Dan Warrener

dwarrener@rmauctions.com

+1 519 352 4575
Ontario, Canada

Possessing a degree in Economics from Brandon University, Dan Warrener spent the initial stages of his career working around the globe... read more

Don Rose

drose@rmauctions.com

+1 617 513 0388
United States

Don Rose joined RM Auctions in 2006, after many years of professionally trading sports and classic cars, and after earning a reputatio... read more

Donnie Gould

dgould@rmauctions.com

+1 954 566 2209
Florida, United States

Donnie Gould joined the RM team in 2002 as a partner and Car Specialist after more than two decades in the vintage automobile auction ... read more

Gord Duff

gduff@rmauctions.com

+1 519 352 4575
Ontario, Canada

Gord joined RM Sotheby's in 1998, initially responsible for the transportation and logistics of the company’s auction and re... read more

Ian Kelleher

ikelleher@rmauctions.com

+1 310 559 4575
New York, United States

Ian Kelleher began his automotive career immediately following his graduation from Oberlin College, with a B.A. in Politica... read more

Jack Boxstrom

jboxstrom@rmauctions.com

+1 818 703 2816
Ontario, Canada

Jack Boxstrom joined RM Sotheby's in late-1996 to assist with the recently acquired, and subsequently record-breaking, auction in ... read more

Jonathan Sierakowski

JSierakowski@rmauctions.com

+1 519 352 4575
Ontario, Canada

Jonathan Sierakowski developed a passion for classic cars while working at a restoration shop as a teenag... read more

Max Girardo

mgirardo@rmauctions.com

+44 (0) 20 7851 7070
United Kingdom

Max Girardo started his career in the vintage automobile industry in 1998, joining Brooks Auctioneers (now Bonhams) as a car specialis... read more

Mike Fairbairn

mfairbairn@rmauctions.com

+1 519 352 4575
Ontario, Canada

As one of the three founding partners of RM Sotheby's, Mike Fairbairn has a longstanding interest in the classic car industry. Gra... read more

Pete Fisher

PFisher@rmauctions.com

+1 519 352 4575
Ontario, Canada

Pete Fisher was first introduced to antique cars in high school, working for Classic Coachworks in his ho... read more

Peter Wallman

pwallman@rmauctions.com

+44 (0) 20 7851 7070
United Kingdom

Peter Wallman joined RM Europe in 2007, following nearly two decades in the international advertising industry, read more

Rob Myers

+1 519 352 4575
Ontario, Canada

As chairman and founder of the RM Group of Companies, Rob Myers’s entire career has been devoted to the classic car industry. Ro... read more

Shelby Myers

smyers@rmauctions.com

+1 310 559 4575
California, United States

Shelby Myers grew up with the classic car industry infused into every aspect of his life. He had the unique opportunity to watch the R... read more

Vinnie Mandzak

vmandzak@rmauctions.com

+1 310 559 4575
California, United States

Vinnie Mandzak joined RM Sotheby's California office in 2012 as a car specialist, following more than 30 years’ experience a... read more