I think the 8.5 BL is around the same as 12-13 turn brushed...
Make the Final drive ratio to somewhere about 6.5-7.5 FDR...
To do this divide the spur teeth by the pinion teeth i.e.
Question: How do I figure out my final drive ratio (FDR)?
Answer: Divide the smaller gear (pinion) into the mating gear (spur).
Example: 108(spur) ÷ 24(pinion) = 4.5:1 (FDR)
If your car has a gearbox you need to know the gearbox reduction ratio. We'll use the Associated B2 ratio of 2.400:1 for an example.
Divide the pinion into the spur then multiply by the gearbox ratio.
Example: 85T (spur) ÷ 16T (pinion) = 5.3125 x 2.4 (gearbox) = 12.75 or 12.75:1(FDR)
What this means is that the motor makes 12.75 revolutions to every one revolution of the tire.
WHAT CAR U RUNNING...?
