water in oil after heads swapped

Well, finished job. Apparently a corroded timing cover is not too uncommon, as the first timing cover I pulled at the Upull was also eaten thru at the block side. Replaced cover and no more water in the oil. What a nuisance, pulled the intake twice and the heads trying to find something that wasn't there. I've never seen a corroded through timing cover but that's what happens when antifreeze is not used. I think the problem was there for some time. The original owner installed a new water pump and new radiator, probably because it had a mysterious slow leak that could not be found. I can imagine that it kept getting low on water but he wasn't able to find the leak. No wonder, it was internal. Anyway, thanks again for the responses. dan....