Ford kind of put themselves in a situation of having to develop their own engine after all of the finger pointing between them and Navistar over the 6.0L debacle. Navistar had no problems with the 6.0L. But Ford turned the wick up a bunch on the motor and it didn't live well or long. Had Ford and Navistar been more honest with one another and more cooperative, maybe things would have been better for both companies and their customers. The 6.4L does indeed seem to be a better engine so far. Too bad fuel economy has suffered due to the EPA mandated DPF and regeneration cycles.