In 1931, Buick made an important shift from its long-running six-cylinder engine, replacing it with three all-new straight-eights. The new engines incorporated such innovations as oil temperature regulators and thermostatically controlled radiator shutters, like those used on Duesenbergs and Packards. Displacing 345 cubic inches, the largest of these engines was fitted in two brand-new model lines, the Series 80 and 90. The latter was the first Buick of its name, a model that would challenge Cadillac head-on in the decade to come—and already did in 1931, with its 132-inch-wheelbase chassis and luxuriously trimmed Fisher bodies that, in many cases, were indeed shared with Cadillacs.

Unsurprisingly, the Series 90 is now held among the finest Buicks, and is one of the few to have been accorded Classic Car Club of America Full Classic status.

The Sport Roadster offered here, one of just 824 made, was owned by Clare Gore, a former national president of the Buick Club of America. In 1983 Mr. Gore sold it as a project to a successor in that role, Paul Rieker of Long Beach, California, who undertook a ground-up restoration that took some four years to complete.

The car was finished in rich Everglade Blue and Ebony Black, with Normandy Gray accents and cream striping, a black leather interior, and black Haartz cloth, creating a truly striking combination of hues—identical to that featured in the Buick catalogue. An impressive roster of accessories further accented its appearance and included Pilot Ray driving lights, a radiator stone guard, dual side-mounted spares with mirrors, and a trunk with fitted luggage. Mr. Rieker displayed the car extensively, winning many honors in West Coast competition and a CCCA Senior First Prize. It was also very successful with the Antique Automobile Club of America, achieving the James Melton Memorial Cup as the outstanding Senior car at the Western Spring National Meet, and eventually earning Preservation honors.

In 2004 Mr. Rieker sold the car to well-known collector Craig Ekberg, also of California, who three years later passed it to a collector in South America. The Buick eventually came back to the United States and was sold several years later into the present collection. There it has remained since, with its restoration still in overall beautiful condition, exhibiting only small signs of age and use, thanks to display within the owner’s private museum—testament to the quality of original workmanship.

Today, this is still one of the nicest of its scarce kind and remains a worthy challenger to any Cadillac.