What does the 5/8 shaft have to do with anything?? You looking for a charging system to put on the PTO side of the engine? Not so sure I am following ya. The lighting coil stator on a whatever crank h30/hs40/hs50 should all be the same but the aluminum flywheel is different-smaller taper. It might use a 5/8" nut to hold the flywheel on but other than that still can't figure out the 5/8 shaft concern. :shrug: