I don't see a win in either of these. If your looking at trucks in this stage of their lives, than I assume you wouldn't be excited about paying thousands more in repair costs. That fact removes the FORD 6.0 from contention. Your odds would be better going to Vegas and putting your truck budget on the Roulette wheel and choosing red or black. I know you don't list GM, and I assume if getting something newer isn't an option or you would be doing it. If your looking at trucks with this kind of miles, do yourself a favor and consider the GM 6.0. There is not a more proven, bulletproof engine on the road today. There are many contractors here and everywhere that have more than 300K on them. Something to consider....or not.