This only ramps up when you have multiple of the same letter "bodies" used by the same manufacturer, as is the case with the GM A-body. The pre-1960 A-body used on the Bel-Air, Nomad, and so on? So GM had this FWD econobox platform, but what about the traditional RWD stuff? This new G-body is a continuation of a premium-model A-body from the mid-70s, also called G-body; ostensibly the same platform, just updated to 1980s standards. In other words, think of the G-body as the continuation of your RWD muscle cars — Monte Carlo, Grand National, etc.