Leaky Slant 6

check your spark plugs. i had the same issue, change valve cover gasket and still got leaks....turned out after asking around on the forums, my spark plugs go down into tubes. someone recommended i replace the gaskets for the tubes.
the gaskets were SUPER cheap since they were just some O-ring type things. did that and problem solved.

just thought i would throw that out there, i would have never figured that out on my own.

pull the spark plugs and the little metal tube will pull out, might be a little stuck but i pulled all of mine with with my finger, slide off the old gasket, slide on the new and put it all back. was a very simple fix, within a few days of driving my motor had completely dried up, now the only leak i have is around my oil cap from steam.