If geared to keep the MM's temp in check and with a fan on the MM, it could work. However, I would bet that gearing would result in the motor being undergeared. That motor could draw a lot of current. I think those KB45XL motors are better with HV due to their higher power rating. (UH rates that motor at 3500+watts, and 5s2p A123 is capable of 2000watts peak, so at 2500watts that motor would require something like 250amps!)
SH Z-Car, Custom Crawler, 8s Savage, 12s XTM XLB 1/7 buggy, 4wd 4-link rear/IFS Pro4 truck, Custom Hyper 10 Short Course, Belt-Drive Mammoth ST 1/8 truggy, 4s 17.5 MM Pro HPI Blitz
It's virtually impossible to know without measuring it. There are so many factors involved with that, including terrain, tires, gearing, driving style, capability of batteries/temp of batteries, ESC settings, drivetrain smoothness, etc. (BrianG's opinion)
Aside from that, assuming the MM weren't already too hot and the batteries could put out a lot of current, I'd guess it could easily spike to 150amps.
SH Z-Car, Custom Crawler, 8s Savage, 12s XTM XLB 1/7 buggy, 4wd 4-link rear/IFS Pro4 truck, Custom Hyper 10 Short Course, Belt-Drive Mammoth ST 1/8 truggy, 4s 17.5 MM Pro HPI Blitz