Piston Rings

I would remove the oil galley plugs and take it to a local do-it-yourself car wash and blast the oil galleys out with a pressure hose.

Also check the cam bearing oil hole alignment by straightening out a wire coat hanger and sticking it through the oil feed holes in the top of the main bearing saddles and also poke it through the oil feed holes to the head. this will help make sure that the holes are not plugged and the cam bearings are lined up when you see the wire poking through as you look through the cam tunnel. The holes for the cam bearings should not be blocked more than half way (half way overlapped or less) for misalignment.