I don't think that you'll be able to gear the 7700s to run without thermalling the esc. I ran a 7700 on 3S in a T4 and wound up having to go with the largest spur I could get, with the smallest pinion I could use and get a decent gear mesh, and had to go with the smallest tires that I could find; all just so that it would stop thermalling. Perhaps you have more gearing options with the emaxx.