burning a hotter grade fuel...and EGT gauge

[E'sStrokr01]

I know that there are #3, and #4 fuels that are supposed to be way hotter than #2 fuel. These fuels are supposed to be prepared for the most extreme colder enviroments, and I know that these fuels are NOT advisable to use in our 7.3's (as well as most other diesel engines). I would never intentionally put these higher number fuels in my tank, BUT - in the event that this fuel inadvertently found it's way into the fuel system, would the EGT gauge register as hotter, etc, and help us to protect the engine? Or could it run hot in the combustion chamber and still cause damage even though the EGT gauge reads normal????



Thanks