okay i have a 91' ls and im about to redo the vaulves but my friend suggusted that i should take it to his mechanic and have them bore it .60mm over and drop in some new weisco pistions and do a whole new head and i got to thinking its not a bad idea im getting horsepower increase and the enging is going to be underwarranty and also it saves me time from having to do it. so i just wanted to know if any one knows what a job like this would cost and if someone could tell me some performance numbers i might expect to see in HP.