Oil blow by

[truckin 79]

In my 79 I have been getting blow by into the air cleaner. I don't drive the truck much it is just my junkyard hauler. I have heard all kinds of things from worn rings, excessive crankcase pressure from carbon build up to bad pcv valve. The truck does not smoke on initial startup but after sitting in junkyard park lot for a couple hours it will smoke for about a minute. It does use oil but I think that is from a oil pan leak that is seen on driveway. Anyone dealt with oil blow by and found a good solution?