This generation was also the first to install a V6 engine, and the car was called the Debonair V, with a badge on the back of the trunk, and a "V" hood ornament. The name also continued the naming of the various iterations of the previous generation Debonair by Roman numerals I, II, III, and IV, an approach shared with the North American Lincoln Mark series and the Jaguar Mark 1 on a luxury car. The Roman numeral identification approach was also used on Mitsubishi's top-of-the-line sports car, the Mitsubishi Starion to identify specific trim packages. In the fall of 1989 a twin-cam version of the three-litre V6 with four valves per cylinder was introduced, by which time the supercharged two-litre was dropped as the regular two-litre engine received a power upgrade. Power for this version jumped from to . This engine became the only option for the AMG version. Top speed for the 24 valve V6 is according to period sources.