Revo/Tekno Conversion Questions

I put in the Tekno conversion for the Revo a couple weeks ago. Since then, I've been fighting heat issues. I'm using a 8XL with a Mamba Monster running on 2 7.2V GP3300 packs in serial. With the basic 15T clutch/38 spur and 2 speed standard trans gearing, I'm measuring temps of 120 on the 8XL, 98 on the MMM, and 165 on the battery packs (this on a 90+ degree day) after about 12 minutes of runtime. Of course, the batteries are concerning me at this point. From the various posts, it sounds like I need to drop down on the clutch bell teeth and/or increase the spur teeth count (correct I hope).

So, to get around the questions, what would be the recommended gearing for an 8XL running on NiMH (12 cells)? I'm not looking for race speed - just some bashing around the backyard. One other questions - I've been setting up my eLogger, but can't seen to find the pole count for a Feigao 8XL. Anyone know what the specs are for it?