Originally the Series 50 had a 331.4 cu in (5,431 cc) Buick Straight-6 engine developing 99 bhp of power at 2,800 rpm, and Buick manufactured 28,204 cars. In 1930 all Buicks were installed with the all-new Straight-eight, and the 1931 the model remained almost unchanged, aside from minor appearance changes. With the introduction of the Marquette Companion brand, all Buicks were repositioned upmarket as junior luxury brands to Cadillac, while the Marquette took the lower price alternative for Buick dealerships.
(Description text adapted from https://en.wikipedia.org/wiki/Buick_Super)
