My 72 K5 (350/350) puts out a small plume of blue/white smoke (oil) every time I start it up after its been sitting. After the initial cloud, the thing runs without any noticeable smoke. The plugs all look good (no oil deposits or ash), so I'm hoping the oil is not blowing past the rings (good compression on all cylinders). My gut feeling is that oil is leaking down my valve stems into the combustion chamber. I bough a set of valve stem oil seals (small black rubber o-rings that go in the valve stem groove right below the valve lock), and have installed them in one head, but the smoke is still there (I run dual exhaust with no crossover). I do not see how these would seal any oil out of the combustion chamber judging by their location on the valve stem. My question is this: Do I need to replace the valve guides to keep oil out of the combustion chamber? Are there any other seals that I do not know about in the valve train that I can replace? Any help would be much appreciated!