If you cook the block to clean it the plug can come out. Machine shops that don't know Mopars wouldn't even know it was there. Just a thought. toolmanmike
that plug better have come out. It's part of the "strip and clean" routine. If it's left in, all kinds of debris goe thru the engine's oiling system when it fires again. You ant get a cleaning brush past it, so there is always stuff left there. I've also found a 2nd plug installed over the first because they didnt remove it, and the next guy didnt notice...NICE...