Trying to simplify what became a confusing post. Rebuilt 4.3 1989. Ran for only 15 minutes total. Heads and block were checked for cracks by engine shop. I have water in my oil already. Pulled intake and cannot find anything that looks like a leak. Pulled the exhaust riser and they looked pretty bad.... I heard two theory's... Some say water will not get into oil from the risers, others say it's possible. My brain tells it's not likely but i really want to believe it's possible because i don't want to pull the heads AGAIN! Any other tips on how to locate the problem? I'm running out of ideas you guys have helped me a ton in the past.... Thanks in advance.