Mention the job of removing exhaust manifold bolts to an amateur mechanic and you'll get an involuntary shudder. Heck, many professional mechanics can't utter the phrase "exhaust manifold bolt ...

The engine should be at ambient temperature before removing the six9/16-inch bolts that retain the exhaust manifolds. It's typical to findthe exhaust-manifold bolt heads corroded away.

For example, exhaust manifold studs are notorious for corroding the shanks thin as twigs, and are just as easy to break. Is the bolt actually rusted or does it have locking compound?

Read about this 5.9L Dodge Cummins ATS Diesel exhaust manifold upgrade in this tech article by Diesel Power Magazine.