On the photos of that motor, there doesn't seem to be a PCV valve anywhere. If that is the case, I would suggest correcting that situation. All motors in normal circumstances need to have a source of fresh air for the crankcase. I believe the draft tube and filter/oil cap was used for most of the 235 production run. We had a 1960 Pontiac with a 261 and it came from the factory like that.
