If you do decide to go the Cummins swap route, look at
DESTROKED: Cummins Conversions They have everything you need to make it look stock and not Frankenstein'd. This is what I'm doing with mine, as soon as the warranty is up. I've owned several Dodges, and my opinion is that their powerplants are superior to both Ford and Chevrolet, but what made me buy this F350 was the price and the interior; in that respect, Ford blows Dodge out of the water in comfort. There's a guy here in San Angelo who has already destroked his F350 King Ranch...I had to look twice, when I saw the Cummins badges on it. Right now, I'm spending $600/mo. on fuel, and I'm babying it at 55MPH and getting 10.5MPG...the Cummins will get you at least 7MPG more.
My $.02
