Excess blow-by (smoke) is usually an indication of bad rings or excessive wear in the cylinder walls. I have seen the top of the piston with a hole in it or ate away at the edge down to the ring land, just not very likely on a stovebolt 6. A compression test along with a cylinder leak down will probably give you the answer you are looking for. Spun bearings usually begin with some racket and then they progress to oil dripping from holes in the pan.
