what rpm are you running, i got mine at .060 and i am running 10% over stock on my minnie 585 without a turbo, that is plenty for my rpm but i didn't want to risk it, remember your intake valve is the one to really watch as it is opening as the piston is comming up, not that they are both importin but the exaust is closing, i checked it by assembling my engine and rolling it over wirh a degree wheel and used light springs on the vlaves and a dial indacator and gently bounced the valve off the piston as i turned it over by hand and watch my readings, a guy could use clay but didn't have any, dont forget to set your valve lash and tourque the head down it will make a huge differance
some guys will run them way closer and some will say i dont have enough
good luck
not much info to go on here? have you put a cam in it? or aftermarket rockers? if not you wont need to worry about a valve hitting a piston. I agree with .060 i would even go down to .050 but thats it.
