That's kinda my point. At that point it seems ford isn't trusting in it's powerstrokes capabilities. And the highest power rated cummins in the F650/750 makes less HP that the 3/4 and 1 ton trucks.
Are they putting Ram 3500 Cummins in F650/750 sized trucks?
Cummins, Detroit Diesel, and Caterpillar all make engines for semi-trucks. Powerstrokes, and Duramaxes are not found in semi-trucks, and bigger trucks in that size class.