Technical advances in diesel engines and drivelines.

A 2012 cummins will run regular about 210 degrees in my cummins pickup. In my coach we run at 180. Both are normal but one is hotter then the other and in rear radiator coaches the issue then is cooling and the extra space needed for the radiator. The new Foretravels have much bigger radiators now then a few years ago on the same engine. Also I bet your 450 horse us an ISL not a heavy duty ism or ISX.