J1A1H XXL Torque Monster Buildup........

[suicideneil]

Yeah, that'll be why its running hot.

I know everyone wants a super fast truck, but to reach those kind of speeds, you'd need a more powerful esc and much larger motor, in a truck weighing this much. I'd say something like a HV boat or plane esc sold by Castle would be great as you're using mech brakes ( no need for esc brakes or reverse ), and run more like 8-12s lipo with a ~1000kv Neu 1527 or 22xx series motor. The 1520 is a large motor, but it physically cant pull that gearing in a truck that weight ( the 1515 tops out at about 65-70mph max in an emaxx or erevo weighing 9-10lbs on 6s lipo, gearing higher just causes more heat from current draw, but wont make the truck go any faster )- you are asking the impossible pretty much

Definately gear for 40mph and see how it does, otherwise you will indeed need a more powerful motor and esc...