1990 5.7l with a .470 lift cam , is there going to be a clearance issue between the valve guide and the valve. Is the rocker going to bottom out on the guides and bust my heads.. If so what should i do.
Get yourself a degree wheel and check. A valve stem usually has about 1-1/2 thousandths of an inch of clearance between it and the guide to allow movement and lubrication. Your camshaft has no bearing on this clearance. If you want a wild guess as to whether or not you might get coil bind in the springs, rocker bind against the rocker stud or even valve spring retainer smashing into the top of the valve seal then my guess is not, not with just .470 lift. Probably would take more like .500 for any of that to happen.
I don't think you know what you're asking. Clearance between the valve and the guide is necessary for lube and alignment of the valve. Not too much though or there becomes an oil burning issue. Are you asking if the cam is going to move so far as to make the rocker tip down and hit the top of the guide? If so, do the math.
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