You've got a lot of options since your engine runs as-is... (maybe off just a little... smokes at start.)
You could shift a chain 1/ link - reassemble, test, pull back down and then do what? Ask Sixto how to thread in a new chain and reset the sprockets - so you start to get a clue about what you could be in for... (And we who've opened these heads think you might have good engine - because it runs!)