Still burns oil

Complete rebuild at 130,000 miles ,top and bottom end. Now has 160,000 miles. Used cast iron rings, after the re-bore. of course new everything was included. I understand that it can take some time for cast iron rings to bed in but 30,000 sounds like it should have resolved by now. I thought it was the PCV valve because it smokes like hell at 850 rpm in idle. Thanks in advance . Howard