I don't have a tremendous amount of sympathy for those that chip their trucks and then blow things up.
BUT the 6.0L is a flawed design. Or rather, Ford is running it at HP levels beyond what International designed it for. That's why people are going in for service and finding their trucks have less power. Ford is turning down the HP levels to try to prevent the head gasket failures.
Now, International knew what HP the 7.3 was producing, and they knew that the 6.0L would need to produce more to keep up with the HP wars.
Diesels are crazy critters, all you need to produce more power is to add more fuel, which nowadays is computer controlled. And you can keep adding fuel until combustion pressures and temps become so high that things start breaking.