Will the Orion 3200 Carbon Spec LiPo battery work with a 3.5 brushless motor?
How about 7turn brushed?

It may be close depending on how hooked up the track is and how long the race is.

If I were running full blown MOD, I'd want the 4800...and if I couldn't go that route...I'd make sure I had a LIPO cutoff and adjust gear ratio to the run time.

I ran lipo 3200 / 10.5 and it ripped on a 365 ft oval. Its was the same speed as nimh 4200/ 7 turn brushed. You may want to run first 1 min or so and check temp.