Steve, is this the syncro thatw ent over Ladysmith Pass into Telluride about
a year ago? If so, I'd think the engine basically sound if there has been no
significant change in performance since then.

Ias I mentioned I have no experience removing a cylinder with the engine
still installed. If it looks like you have clearance, pull the jug and see
how the piston and cylinder look, fix that one to see how it goes and then
decide if you want to do it three more times.

A crack between valves sounds bad. Take it to a local machine shop and see
what they say.

Keep us posted and good luck
Thomas Forhan