You're right Turtle. I didn't word that very well. More air does lower exhaust temperatures and help the cooling system out but I can't claim this 300 HP 6.5 could survive on the stock cooling system. However my daughter's bf has pulled a 14,000 lb stock trailer through the mountains with it and had no issues whatsoever. There is a shop close by my home that rebuilds the 6.5 heads I could send you his contact info if you like.
The total cost of this project was over $16k but he bought a complete engine with new fuel system and turbo. Then we replaced the entire cooling system, clutch, flywheel and starter, brakes, ball joints, tires, exhaust system, alternator and the power steering pump. Now the gauge cluster is acting up .... It acts as though it is a bad ground because multiple gauges quit working. (No speedometer or odometer, no fuel level, oil pressure reads lower than actual, engine temperature and TAC are accurate).