I'm wondering if the gearing would be ok for your motor if you switched to 48DP gears and used the biggest spur and smallest pinion possible before the motor can hits the axle.
Otherwise, what about grinding the timing tabs on your motor so that you can rotate the endbell and reduce the timing - that would cool it down. Plus then you could use your mountain of brushes up.
Also I don't know how much tyre thickness you were running but if it was a lot this will obviously cause the motor to run hotter/be over geared. Hoping to be able to run with you on Friday...
__________________
|