That early PCV valve is unobtanium , take it apart and clean it , there's a tiny orifice that plugs up , easy to clean once you know to look for it .
That spring in there is delicate too .
That PCV is the _best_ thing you can add to your engine - keeps it clean inside .
Good job on your find , I'd just run a by-pass oil filter as you _will_ be changing it regular like , right ? .
