The 150, in production from 1957 to 1961, was the final model of the XK series, which started in 1948 with the XK120. With the XK150 this type of car moved away definitively from the C and D competition, getting a little bit more "bourgeois" but also acquiring more ride comfort. The standard XK150 was equipped with a 3442cc and 190 horsepower 6-cylinder engine (the same as the XK120 and XK140); from 1959 an even more powerful version was available, with an engine brought to 3781cc and 220 horsepower. This XK150 3.8 is the most sought after version of the 150 series.