Years ago I put a low miles junkyard 340 in my 70 RR ( the FIRST gas crises) I ran that thing a week or more before it stopped burning oil. It had less than 20,000 miles on the wreck (I saw the car). I even ended up complaining to the wrecker. He assured me it would be OK and that they'd stand behind it. I put over 80,0000 more miles on the engine, before it got torn down and went into the old FJ40