Time to shut up guys, buy the first issue of Diesel Power mag, it tests all three empty, loaded, towing flat and up hill. The Ford beat them all hands down....all. Just get the mag, read it and then go piss on your GM, Dodge and if you have a Toyota just set it on fire. I am serious, the ford beat the crap out of them in every category. Read and then post back. I have a 7.3 Excursion, 2003 with 84k and it has only had oil changes. Now the Dodge Cummins is a great motor, no doubt, but they wrapped it with tin foil. www.dieselpowermag.com read it a weep...unless you have a PSD. As far as why it is not in a boat, it is simple, no one in the after market makes parts and it is just not supported by the marine industry so why reinvent the wheel.