rippintare,
Aren't these fixable by a good automotive machine shop. I have seen pretty nasty cracks repaired by the drill and plug method.
This would require two new seats in that combustion chamber, but I have had that done several times on cracked heads. Maybe location doesn't make this type of repair feasible.
If the 261 head is specific to that engine, it might be a bearcat to find a good replacement.
Stuart