[DwightSchrute]

the 80+mph 1/16 revo's i've seen were running 2 SMC 2200mah 30c in series and 75+mph 3S Thunder power 4200mah 40c.

I don't know if you're splitting hairs over 400mah, but for larger scale models, higher mah will have a definate effect on acceleration and how fast you can get to top speed.

the neu's can be amp hogs and if the battery is too low in milliamps, it's definately going to effect acceleration. so there in lies another problem.

in theory, a lower mah battery should be able to get to the same top speed as a slightly higher mah battery, but it will take a longer distance to do so. if you don't have the space to get to top speed, hold it, and let the motor completely wind out, it dosen't suprise me that low 70's is all you're getting. i think the solution is either a longer road or slightly higher mah packs.