I car does a little of this, and like yours the oil and coolant are fine. I wasn't able to diagnose the problem in time for winter, but I believe my problem is gas. Either from the cam overlap, clean heads, or junk additives, there is no mistaking that it smells like gas. I still have to retorque my new heads, so maybe there is some cylinder leakage, but I've heard the Fel-Pro blue gaskets are supposed to be okay without one. Maybe it's the crap AC Delco plugs I run, or a bad coil? Can't say for sure, but I can say when I took my phenolic spacer off the driving smoke decreased, probably due to better atomization in the Vic Jr.
And for the people who say white smoke is not gas, run a carb with no primary jets and tell me what color the smoke is...