Welcome to the Forum - I'm new here also - great place for answers. We are originally from WV so yes you are doing some mountian driving. Here is some info. from "Experts" site - looks like you may have a temp. problem..?
Expert: Harry Jacobson, P.E.
Subject: 7.4L Low power and Overheating
I have a 1996 Chevrolet 3500 HD the entire cooling system has been replaced with new parts and I still seam to have a problem with the temperature running about 220. It dosen't seem to have the power that it should have for such a large displacement. The truck has a little over 50,000 miles on it and has been expertly maintained its whole life. This has the mechanic who has always serviced it and myself puzzled. I will be grateful for any suggestions.
The operating temperature is too high and will, if it has not already, damage the engine.
A vacuum gauge is still one of the best diagnostic tools out there. It can tell a mechanic about the condition of the valves, valve timing, and exhaust system as well as detect intake leaks.
In fact, one of the things I would check for is a restriction in the exhaust, either in the catalytic converter and/or muffler.