I found this double-shafted motor that I felt would be a good size for my swing drive and easy to add a flywheel-
The seller didn't know the RPM so I put together a quick test stand. I decided to use the square drive plastic gears from vex thinking they would save me some machining time. They work good for testing but are a bit large and take up a lot of space. I used these extra large gears to find the RPM of the motor-
The motor runs at 4950-5000 RPM on 12 volts. Now I have to make the swing gear-case that will reduce down to approx. 9 RPM and the swing gear and pinion will reduce it to 1.5-1.6 RPM.