At launch, the 2 litre versions of the 800 used two naturally aspirated 2.0 L 16-valve developments of British Leyland's stalwart O-series engine, dubbed the M series. However, in 1988 an 820 Fastback (no letter after the 820 badge), with a single carburettor version of the O series was launched for the fleet market. The M series was divided into two versions; the M16e fitted to the 820e/se, with single point injection, and the M16i which was fitted to the 820i/si with multi-point injection, i.e. 4 injectors – the engine management system derived from that used in the MG Maestro and MG Montego models. The top 2.5 litre versions (825i & Sterling) used a Honda designed V6 unit in 2.5 L capacity. Initially, only a saloon body was offered; a liftback version – referred to as a fastback – became available in 1988.