A bit throttle to half throttle isn't any dilemma and won't give vibrations btw. I'm undertaking 28 mpg max now with simple driving and in some cases reving to max 7k, but only often! – Belt travel pulley width: To permit to the 2mm wider belt the Blacktop cam belt https://laneggaco.nizarblog.com/29239470/blacktop-4age-for-dummies