ORIGINAL: RCBruski65
If you are going to use six cells, I would also look at the Hacker A50-16s with a CC Ice 75. That is what I have in my Miss Wind Bipe and love it. In the air it only pulls about 60 amps with a 16x12 Xoar Wood prop.
Just to help the OP:
The Hacker A50-xxS motors are the same size/weight and relatively same power rating. The A50-xxL would be longer and heavier. The motor suggested by RCBruski is a lower kV than the E-flite, so you will get lower RPM. But note he is using a 16x12 instead of the 17x7 as suggested on the E-flite page for the Beast.
The difference between the recommended E-flite motor (or the A50-12S I suggested) and the setup suggested here is sort of like "3D vs Pattern". For Pattern/IMAC flying we like very smooth aerobatic flying with relatively constant speed. In 3D guys prefer large diameter props with less pitch for slow, high alpha maneuvers.
If you really like pattern and want to practice graceful, precise aerobatic flying then RCBruski's suggestion is a good one. Either way you will have a setup that is within the recommended limits of that airplane (power, weight, size, etc). His suggestion is also going to be a little more efficient and give you longer flight times.