All depends on the setup. My engine has a lot of work done to it, 10.5:1 compression, .040'' over, pro rocker shafts, dual springs, big valves, adjustable cam gear degree'd to spec, pro oil pump, handles over 8000rpm without a fuss. Not that I like to run those rpm's but it can take it. I set the valves to .007 and .011 but its all personal preference.
