I have a 305 with 70K miles. I rebuilt engine down to short block. Left the pistons in an checked the bores, could still see some crosshatch in the bores. The worst bore was no more than .003 out of round. Heads are rebuilt with new seals, valves, and springs. Engine runs great with no visible oil or smoke coming from exhaust. But It uses ~1qt of oil every 1250-1500 miles. Is that acceptable for a engine with 70K miles? Like I said before engine runs great.