Quote:

do you think jump 450 stock cam lift to 480 lift really needs clearence check?

if so, then nobody could install a modern grind cam , or even a stock MP 509 camshaft

then if changing also the camshaft to a modern cam grind DEFINITELLY will need to be checked

anyway is true, check everything is a good advice, but some cases I don't think DEMANDS a check




It isn't valve to piston clearance thats an issue... It is pushrod to cylinder head & block that can be a problem... To change the ratio the effective leverage (ratio) is changed.. Your not changing the distance of the valve stem to the center of the rocker fulcrum so therefore you must be changing the distance from the center of the rocker fulcrum to the pushrod.. To increase the valve lift you need to shorten the distance from the center of the rocker fulcrum to the pushrod... So that potentially brings the pushrod into contact with the block or head...