This is a list of engines produced by Mitsubishi Motors since 1964, and its predecessors prior to this.
These three branches (Mizushima, Nagoya, and Kyoto Engineering Works) were established as clusters of the many small aircraft factories built during the war.
The numbers do not in any way relate to each other or across letter codes and were purely issued in order of development.
In 1964 the three companies were merged into Mitsubishi Heavy Industries and eventually a new naming system emerged.
Where engine codes are used which include the supplemental letters, the first digit denoting the number of cylinders may be omitted, so 4G63T may be seen as G63T.