yeah, once you get to milling or changing cam lift with a b-series vtec head on a stock ls bottom end, you're going to have clearance issues. I do not know much about doing what you plan on doing, but I am familiar with it, and I have heard that if do anything more than put the head on with the stock internals that you will have a serious problem, or four!! ! the best bet is to change out the pistons for pistons with bigger valve reliefs, as that is the major problem. but do not listen to me, as I do not know a whole lot, but I am willing to learn as this idea is my next step!