Patterman,
I have mine ordered to be delivered this week and will be powering with a MVVS 58. I presently have 2 of these motors and they are crazy strong. My WH Edge (about 18.5 lbs.)will hover at about 1/4-1/3 throttle and pull out like a rocket out of sight. Plenty of power. I have read that it rivals any 80cc on the market.

Technical specifications from the manual

Bore 42 mm Stroke 42 mm
Weight of complete engine without ignition* 1820 g
Fuel Unleaded 95-octane fuel
Maximum power output ** 8.5 HP/6950 RpM
Weight of ignition unit 165 g
Lubrication Oil with petrol in mixture 1:40
RpM range 1000 – 7500 RpM
two-blade propellers:
22x10, 22x12, 22x14
24x8, 24x9, 24x10, 24x12
25x7, 25x8, 25x9, 25x10, 25x12
26x7, 26x8, 26x9, 26x10

three-blade propellers:
22x10, 22x12
24x9, 24x10, 24x12