just to give you a idea how good they are, as the boys said just putting the tb v2 head on increases power drimaticly!! im oppioning if your putting it on a 160HO or a 155 you will be more then happy wiith the response it will make provided a good carby tuning and really reliable using standard pistons. v2 heads are now all along the board being avaliable for import 88 motors crf50 motor gpx 125's so you really cant go wrong and with the price tag thats somwhat affordable compeard to taki or kitaco gear its good bang for your buck