Unbolted the flex plate. Nothing there and not any positive proof that anything had been there. Checked every rod bolt, didn't go to full torque. Enough to know that was not the problem. Turned the motor over by hand, with a light and checked every cylinder. Very carefully looked at everything. Not a sign of any dings or scratches. Rechecked rocker arms, valves, springs and everything I could think of. Whatever it was at one point fell out or vaporized. So,,,,,, my son and haven't asked my nephew yet, we are putting the motor back together this weekend and put the car back together. With a prayer !