I know you said you have a lot of "steam" coming from your breathers. When I built my first engine I thought the PCV looked stupid and left it out. About two months later my plugs started to foul out every day. Yea thats right, I blew every valve seal in both heads. I now use a tee in the back of the 4160 for the PCV. That steam is either the seals or the rings starting to go.