the BIG question is FOR what? is it currently In another vehicle, on a stand? INFO? As 69 pointed out that back pass side cyl is known for issues, so it would be a good time to tear it down and rebuild which is fairly simple. Mic it out you may not even need to have it machined depending on mileage on it. In my book if you are swapping engines, and the rig that is getting the transplant is still running, always rebuild, so you have a fresh mill, it just saves headaches down the road.