The first generation of BMW 5 Series was introduced for the 1973 model year. Known as the E12, this first generation of 5 Series was available with either an inline four or inline six engine in various displacements. The most notable of first generation 5 Series variants was the M535i, which is considered the precursor to the later E28 BMW M5. Other variants included the 518, 520, 520i, 520/6, 525, 528, 528i, and 530i. As was common for many BMW models, the E12 was often used as a Race Car. Built until 1981, the E12 was replaced by the E28 5 Series in 1981.