I disagree. What Cat or Detroit is going to fit in a Superduty? Even a C7 uses hydraulic injectors. I had one in my service truck that I drove for 5 years and I loved it, but it's potential is limited by the injection system. I did however have tons of low end, the type that comes from an I6.
The billion dollar industry that relies on torque ie. big rigs, tug boats, heavy equip. stick with the I6 design for a reason. Even Ford puts the Cummins in the F650 on up.
Have you put a V8 and I6 diesel head to head with a load? With no load you may not tell the difference or even feel that the V8 has the edge in the upper rpm. The difference is the low end, moving the load.
I'm not talking about drag racing, but pulling power. I'm no genious, but I have been a diesel mechanic for 17 years in the heavy equipment industry. Part of my job is performance testing and I have operated all types of equipment in an array of configurations and my choice is the I-6. Just my opinion. What can you show to back up the V8/I6 low end comparison? 200rpm is a significant difference when you are trying to move something.
BTW the way my build thread is here:
http://powerstrokenation.com/forums/showthread.php?t=132705&highlight=
FWIW the Cummins low end would have pulled the guts out of my fairly modest 7.3. I have some videos of my 7.3 and still need to get some of my 6.7. I'll post them up eventually on my build thread.