Editing BMC B-series engine (section)

===Numbering system, 1970 onwards ===
Beginning in the early 1970s the numbering system was simplified to "18 V" plus a serial number, where 18 represents the capacity and V = vertical, ''i.e.'' longitudinal (in-line, not vee-arranged) engine with [[rear-wheel drive]], and H = Horizontal, ''i.e.'' transverse engine with [[front-wheel drive]].<ref name=number />

There was sometimes a country indicator after the first part of the code, ''e.g.'' "18V-Z" was used for some [[United States]] (except [[California]]) [[MG MGB]] engines.