for them. A highly trimmed, two-door coupe, the first Regal, officially marketed as the "Century Regal Colonnade Hardtop coupe", shared its front and rear styling with its Century parent with distinctions amounting to differing grilles and taillight lenses. The Regal shared the same "Colonnade" pillared hardtop roofline (a hardtop with B-pillars (center pillars) but frameless doors unlike a sedan body) and greenhouse (window area) with the Grand Prix, Monte Carlo, and Cutlass Supreme as well as the lower-priced Buick Century Luxus coupe. Like its corporate cousins, the Regal (and Luxus) featured the newly fashionable opera windows, which were small fixed rear-side windows surrounded by sheetmetal, instead of the traditional roll-down windows. For the first model year in 1973, the Regal nameplate was only used for Buick's version of the GM intermediate personal luxury coupe, but the following year gained a sedan companion (there was no Regal station wagon). The Century moniker was discontinued for 1976, with the model now marketed as the Buick Regal. Interiors were generally more luxurious than lesser Century models with woodgrain trim on dashboard and door panels, along with door-pull straps and bench seats with center armrests with cloth, velour, or vinyl upholstery. Optionally available throughout the run was a 60/40 split-bench seat with armrest. For 1976 and 1977, the Regal coupe was available with the S/R option that included reclining bucket seats with corduroy upholstery. The model lasted five years with minimal changes, although there was a fairly substantial facelift for the coupe for 1976. The sedan retained its original 1973 sheetmetal through 1977. 1976 models incorporated the recently legalized rectangular headlights, horizontally mounted on the coupe, and vertically on the sedan. The Regal coupe sold reasonably well, although it lagged behind the Monte Carlo and Cutlass Supreme which had become the best-selling cars in America by 1976, with a listed retail price in 1976 of $4,910 ($ in dollars ). The Regal was most commonly powered by Buick's V8, which was standard equipment on all models for 1973 and 1974, and optional on coupes but standard on sedans from 1975 to 1977, and the larger V8 was optional for 1973 and 1974 models only. Starting in 1975, Regal coupes came standard with Buick's resurrected V6 engine previously offered on the 1964–1967 Skylark; the engine's tooling had been sold to Kaiser Motors for use in Jeep models (Kaiser was purchased by American Motors in 1970