I think the two teeth versions are 122 and 149. Not sure why mine is 122. Just make sure that your starter teeth model is consistent with the flywheel/starter ring gear. This is interesting
Choose your flywheel based on the lug size for your engine and you can purchase the ring gear separately. It looks like they are one piece since there are no fasteners but it is fairly straight forward to change out a ring gear. I cut mine with a cut off wheel until almost through then broke it loose with a screw driver. The new one is heated in the oven and placed over the flywheel. In a matter of seconds they are literally one piece! I am sure you can find a bulletin explaining the procedure with a quick search.
