In 1985 the engine design evolved again, as it was bored and stroked to 5167 cc and given four valves per cylinder—quattrovalvole in Italian, hence the model's name, Countach 5000 Quattrovalvole or 5000 QV in short. The carburetors were moved from the sides to the top of the engine for better breathing—unfortunately this created a hump on the engine deck, reducing the already poor rear visibility to almost nothing. Some body panels were also replaced by Kevlar. In later versions of the engine, the carburetors were replaced with fuel injection.