1980 saw the arrival of the excalibur series iv, the car that brought about the first real change in appearance of the marque's products. It was also the first excalibur to have glass side windows, a trunk/boot integrated within the bodywork and an electrically operated soft top for the roadster as well as phaeton models. The styling had also evolved a little. It still undeniably evoked vintage mercedes, but this time emulated the 500/540k series rather than the ss/ssk. The series iv was obliged (by even more rigorous anti-pollution regulators) to take on yet another engine, a gm 5. 0-liter (305 cu. In.) equipped with an automatic transmission and a locking torque converter.