Wow! I didn't realize the Cummins was air cooled. All this time I thought that finned thing in the front that you put antifreeze & water into was for cooling.
Too many million mile Cummins powered Dodges on the road to lend much credence to your theory. Sorry, I can't see the logic behind your reasoning there. Diesel engines will usually melt pistons due to failed injectors. In line six cylinder engines, when overheated due to a cooling system failure, will normally sustain the most damage to the rearmost cylinders NOT due to airflow issues, but due to the fact that they are furtherest away from the waterpump, and when coolant is already superheated making it's way through the water jackets in the block, it doesn't do a whole lot of good by the time it arrives at #5 & #6 cylinders.
This is true of long in-line engines, gas or diesel.
Brilliant dissertation Maestro! Bravo!!! I see by the quality of your post that you are obviously a high-end engineer or College Professor. Who am I to argue with a man of your obvious expertise? Your use of technical jargon like "furtherest" indicates a level of expertise that humbles me. It's so simple... You have it totally wrong.