thanks for your imput on it. i started it up on sunday wow it was much louder than the stock 2.5 that comes with the revo. i was comparing the heads of the 2 engines wow big difference. i still have to break it in. I'm doing it the way traxxas tells you to. The manufactor sayes to do it that way as well. i guess its a run off of the heat meathod. this is my first aftermarket engine. i guess i just want to take it slow and make sure its done right so it will last longer.