[captain harlock]

Okay, use 9-10 cells with a gear ratio 11.8:1 and watch the temp of the esc and your motor. The motor should not go beyond 100 deg. Cels. and the controller would stay cool by using a 12 volt fan. Your 8s will take you beyond 58mph easily at 12 volts, so maybe 9 cells will keep your truck at high speed and under control as well.