This the second one on my truck...It is a single chain..
LC engineering has a double chain replacement kit, but it ain't cheap.
I think the tensionor stuck on mine, it is worn worse than the original one I replaced when I rebuilt the engine.
And the short guide disintegrated, not sure if that was caused by the chain breaking or caused it to break.
I haven't pulled the head yet, so I'm not sure what else is broke or bent yet.