I would probably call Meadows and see what their guy says about it....they are still in business, or were a few years ago. I bought parts for my #1 from them, and they were helpful.
In realtime application, I don't know how well a flywheel would work in a sustained cut....might help in a short pull....but if you are having trouble maintaining blade RPM, you need more power. Dropping RPM is a sure way to get an overheated blade, and cupping...and worse problems.