In 1980, GM gave all of the full-sized B and C-body line new sheet metal to tidy up the styling and improve aerodynamics. The basic dashboard design was retained. Also new for 1980 was a two-door Fleetwood Brougham Coupe, which was based upon the Coupe de Ville but featured an exclusive formal landau vinyl roof. The 425 cu in (7.0 L) engine, a reduced bore 472, was further debored for 1980-81 to 368 cubic inches or 6.0 liters in order to comply with newly-enacted CAFE standards. For 1981, the 368 was provided with a modulated displacement system designed by Eaton Corporation, controlled by a digital computer, which locked off intake and exhaust valves to two or four of the eight cylinders, thus running effectively as a V6 or V4 under light load conditions where in third gear, and over . This engine, called the "V8-6-4", was reliable, but the computer technology of the era was not refined enough for smooth operation and it was dropped from all models but limousines after 1981.