i guess no one here has spent $350.+ for a set of valves springs a was hoping they would last as long as they could or did not want spark scater? or you like to think that harmonice will not kill a engine do you know what amplitude of harmonices will break a valve spring ?? but you will put a gear drive in a engine that will put more harmonices in one i guess i do not know what the hell i am talking about and people like tci atc jack roush fluidamper and jesel and me do not know that harmonices are good. and guys like you want to put more in