At the 1965 Frankfurt International Motor Show, Daimler-Benz presented its new luxury-class series with models 250 S, 250 SE and 300 SE (W 108). In March 1966, the model range was expanded by the addition of the 300 SEL (W 109), its wheelbase being 100 millimeters longer than that of the basic model. These models represented the first independent luxury-class series from Mercedes-Benz and were the first post-war luxury-class limousines with eight-cylinder engines. Their special technical features included the patented safety steering system.
The series’ top-of-the-line model added in March 1968 was the 300 SEL 6.3, featuring the V8 engine and automatic transmission of the 600 and hence with the performance potential of a top class sports car. Its presentation at the Geneva Motor Show caused a sensation, especially as there had been no announcements made prior to the event. The 6.3’s only distinguishing external features were its wider tires, double halogen headlamps and an additional set of high beams. The engine delivered 250 hp (184 kW), but of greater significance perhaps was its mighty torque of 51 mkg, which took the sedan from 0 to 100 km/h in 8 seconds and gave the car a top speed of 221 km/h. Although the 6.3 cost over DM 10,000 more than the 300 SEL and was more than double the price of the 280 SE, the 300 SEL 6.3 was the object of lively interest and unit numbers totaled 6,526.