I think you are correct about the bell housing. If I remember correctly, there are two retaining bolts for the housing that are inaccessable, or at least very difficult to reach, with the flywheel in place. Its been a while since I took a bell housing off one of those engines, but flywheel removal was pretty common because careless or inexperienced drivers would often burn out the clutch and destroy the flywheel in the process. Then complain about a $100 clutch job (1950's prices).
Harvester
