Stubby on Nostr: looks like you have it apart already. Do the rings move freely in their grooves? If ...

looks like you have it apart already. Do the rings move freely in their grooves? If this is an overhead valve engine, can you tap the exhaust valve rockers to determine if the valve stems are free and not binding in the head? How about a blown head gasket in the area between the cylinders? I probably should have asked first: diesel?