This raises the question of how many rebuilds you may have actually done !! In ANY rebuild its recommended to check all clearances, passages, etc.. Why? Because of a thing called "manufacturing tolerances" !! Its why clearances are published in manuals !! Who hasn't ground off flashing, opened up holes, found clearances that were too tight or too loose ?!?! I don't think I'd want you building a motor for me if that's your attitude !!There's no reason at
all to be grinding anything on a stock
engine setup.