If you can get a speed tac. on the end of the shaft, that would give an idea of what speed they run. I took a couple off and hooked 2 hoses up and ran them just to test for speed. Not real accurate, but you get an idea of possible starting point. On you machine, I would imagine the motors are quite hefty. On a side note, do you plan on removing any stumps? the vibe plow can serve to cut roots up close making them easier to get out.
The unit looks well made, so it should stand up to heavy use. I probably wont run fast so you may have to see or test that part out before you take it apart, then if speed needs to be increased, deal with that first, then build up from there.
