UPDATE:
Got truck on freeway and ran it up to 76 mph. 76 going up a long grade was the limit, it hit 198 degrees and blurted out coolant. Above 70 going up grade, it will max at 190 and no coolant loss. At 70 or less. It will stay at 183-185 consistantly. At idle it drops to 180-178. I can live with that. Not sure why the system hits limit at 75 mph going up grade. I could probably do 80 on flat ok. Some states have 80 mph speed limits. Get better mileage at 65 anyway.
That's the best I can do with all the cooling upgradegs I've made. Listed as follows 185 degree thermostat, BPD aluminum coolant pump, rerouting coolant filter return into the radiator, the severe duty fan clutch, blue wire fan lockup switch, the next options would a BPD or similar external oil cooler, replace heater core which may have clogging. The EGR has already been removed prior to my ownership. I'm not the only person who has overheating issues with a 6.0 liter Power Stroke as many videos on YouTube demonstrate. At least I have achieved manageable cooling in my engine.
My question would be why is it puking out coolant at 198 degrees when a stock one doesnt even get the warning light on untill 220 degrees? the factory engine runs between 192 - 205 degrees and the thermostat isn't fully open untill 119 degrees.
