I would make sure to check all the oil galley ways. I had a motor built and there was a blockage that the builder thought was clean but when he measured it against the others with a welding rod it was plugged and felt like he was hitting the block with the welding rod. I had some bent push rods and some bluing on other push rods and it ate the #4 main. It was just debris from machining possibly from bushing the lifter bores. i heard the valve noise. This was after about 100 miles on motor.