Engine Temp how hot is too hot?

Thank you all of your replies. I've heard from people statement like these "I pulled that hill going 70or 80 no problems...can't even tell the trailer is back there" etc. etc. So I was just curious if there was something wrong, or if those were just fish stories. I figured the latter was the case, and it sounds like the consensus here is that they are indeed fish stories. The reason I didn't call the service department and ask is that more often the case is that most of those guys don't have real world experience towing and I wanted to hear from someone who has actually pulled similar grades with their own setup. They (the service dept.) certainly could answer the technical questions (i.e. the question regarding the cooling system and how long it could run hot), however, I have also learned that there are Ford, GM, and Dodge technicians who belong to forums like these and could lend their own technical advice coupled with real world experience to the topic. Thanks again for all of your helpful advice.

Eric