Reply to "Exhaust Smoke"

The color of smoke is an indication of the problem.
Black Smoke, is a rich condition dealing with the carb and fuel.
White Smoke is coolant entering into the compustion chamber and could be a bad head gasket or cracked head/block.

If it is blue like you say then you are on the right track, oil related. Since the valve covers are off, inspect the valve seals to see if they are damaged or missing. Simple thing to check without pulling the head. A damage seal will allow oil to leak down the valve stem and into the combustion chamber.

I agree with the compression test. There is a process in performing this test, make sure you do it right. Check all cylinders and look for variation. A dead cylinder will pinpoint the problem with the rings or valves. For the dead cylinder, pour a little oil in the spark plug hold and run the test again. If pressure improves then the rings are likely the problem as the oil will "seal the rings" and improve the compression.

The other question is how bad is bad? One could run with a smokey engine for some time and hold off on a major rebuilt until funds and time allows. Might consume a few plugs along the way from fowling but at least your get to drive it for a while before yanking the motor.

I hope it turns out to be something simple. If it is the rings, they you are facing a rebuild at that point you might as well do the whole thing top to bottom.