depends. when you get them balanced they wil tell you what theirlimit is. I had mine balanced to 9k rpm they shaved to within grams of that. theres no need to go any higherthan stock if you have stock cams you wont gain any more hp. and you might not have a tall enough gear. Higher isnt always better. My Z24 with a redline of 6k rpm would pull harder than any honda with a 9k rpm redline. it just has alot pf factors involved. i cansay balanceing willmake it rev faster and safer and be more stable at higher rpms. gaining you power throught your powerband. just nothing past what the cams are designed for.