Hi Jordan
Swapping the ring gear no big deal, carefully drive off the gear using an oak block working your way around the flywheel. I've heard of people just heating with a torch but I'd be afraid of taking the temper out of the gear. As to heating the gear to put it back on
http://www.mapleleafup.net/forums/sh...ear#post185072 I like an oven first time I did it just kept raising the temp of the oven a little at a time till found the temp where it just dropped on.
Of course be sure to have the tooth bevel to the front, yup first time I did it had it backwards.
As tho matching tooth count by flywheel numbers, I've got a collection of flywheels and have found both tooth counts with the same numbers, think this because of mix and match games that many of these engines have seen over the years.
Last two times I played this game it was to put six volt ring gears on 12 volt 235 and 261s. I was concerned about balance with changing flywheel and clutch assemblies, but the engines seem very smooth so didn't get fancy and seen the units out to have them balance as a unit.
Cheers Phil