The year 1975 brought revised front and rear styling to Catalinas and other full-sized Pontiacs, along with standard radial tires and electronic ignition. The same assortment of 400 and 455 engines carried over from 1974 with reduced horsepower ratings ranging from 170 to 200, but now mated to catalytic converters, which provided improved driveability and fuel economy over previous emission control equipment, but mandated the use of unleaded gasoline. Four-door pillared and hardtop sedans featured new six-window styling with the sixth window on the hardtop sedan functioning as an opera window. 1975 also marked the end of Pontiac convertible production until 1982; the Grand Ville Brougham was the last full-size Pontiac convertible.