You have heating issues because you gear it very tall. I've Slash with mod1 gearing for only speed runs with a 550 size motor and high voltage (5s-6s lipo). For racing a motor like vxl around 3500kv is very ideal. İf you want to have a cool and more powerfull setup go for new tekin or novak 550size short course motors.I tried lots of motors on Slash and after so much experience I think 540size motors are a little weak for a truck like Slash. I ended up trying with a medusa 36/60/3100.