Before you pull the head, try replacing the valve seals. These heads use little rubber rings and truth be told, I have never in 40 years found a 235 where the rings had not already deteriorated and fell apart. It will cost you a little time, a valve spring compressor tool, and some new rings, might just be the lack of rings sucking too much oil past the guides on high vacuum situations.
Last edited by mdonohue05; 11/10/18 07:06 PM.
