Do you mean to say that the leak is inside the valve cover, and that is why it was discovered when changing valve springs? Or is the leak between the head and block, and which side of the block is it on? There is a VERY good possibility that the head is tweaked because of removing the bosses.
Your friend may be looking at taking the block down and having the deck flat milled, and at the same time having the reworked head flat milled too. Just a couple of thousandths off of each is all it takes. And use head studs when reassembling.
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David
newbie #4153
