The Buick Special was an automobile produced by Buick. It was usually Buick's lowest-priced model, starting out as a full-size car in 1936 and returning in 1961 (after a two-year hiatus) as a mid-size. The Special was built for several decades and was offered as a coupe, sedan and later as a station wagon. When GM modernized their entry level products in the 1960s, the Special introduced the modern Buick V6 that became the core engine for GM for several decades and lives on in current upgraded V6 products.
(description text adapted from https://en.wikipedia.org/wiki/Buick_Special#1961%E2%80%931963)