ken is right with the tolerance of sound. at one time i was wondering the same thing just like you. after i got my trucks to stop and steer i took them out. my sound tolerance in my 40 is less than the other two but thats due to some improvements from 40 to 51. i run mine from 0 to 52.5 mph. depending on the condition of the engine you might tolerate the noise but the motor wont tolerate the speed
guess how i know this
there is a sweet spot that the truck likes the best. find it and drive it at that speed.
