Sqwawk, when the heads get too hot, they deform at the joint with the cylinder. That much is known. The joint leaks after deformation which is why Jabiru goes to positively insane lengths to instruct owners regarding cylinder head tightening. This should be a non issue if a modern head gasket was employed, even without going to the modern practice of designing the joint to employ plastic deformation of the head bolts during the tightening process.
As for through bolt failures, the "Cosi Fan Tutti" argument (every one does it) begs the question.