Is it possible to use a 12V ring gear with 168 teeth on a 6V flywheel that had a 139 tooth ring gear? Though I am not able to accurately measure the diameter of the two flywheels where the ring gear fits, they appear to be the same at that point. I'm converting my 6V to 12V and have found that the 10" pressure plate for the 12V flywheel is too large for the old 1941 bell housing and binds at two reinforcement ribs in the top side of the bell housing.