BMW introduced the 520i variant of their E12 5 Series for the 1972 model year. The 520i was initially powered by the M15 version of BMW's famed M10 inline four engine, but in 1975, BMW fit the updated M64 version which had the same displacement and similar performance stats, but had a wider powerband. Both manual and automatic transmissions were offered for this series of rear wheel drive cars, which were only available in a sedan body style. Production of the E12 520i ended in 1977, but the 520i would continue life in the next generation of 5 Series, as the E28 520i.