not sure, my personal opinion, go with the cummins motor.
WIN/WIN ... better power, better price, better motor, better mileage, better dependabilty.
I put a new NA 6.5 in my HMMWV and wish I went with the cummins.
6.5 is better than the 6.2 I had, but still way under powered and gas mileage is still poor even with the 700R4 I have behind it.