I just don't understand their theory, at least from an engine break in aspect. When I break in a (tractor) engine on the dyno, I generally slowly ramp up the power at varying speeds/ loads in 5-10 minute intervals, and after an hour or so am at rated HP. The absolute WORST thing for an engine in break in is idling or operating with light loads. IMO, these trucks just plain aren't working that hard empty driving around. I wouldn't be a bit afraid to hook up a load fresh off the lot and go. Probably not pedal to the metal kind of stuff, but a good moderate load. I understand there are differences between engines used in differing applications, but it's not THAT big of a difference. I don't think they run Semi tractors around bobtail for 500- 1000 miles... kinda makes you wonder what is the exact logic behind Ford's recommendations.
There are literally hundreds of theories/ myths/ tales on engine break in. The best one I got from my engine machinist the other day was a guy that built Detroit engines, I believe. He would get them going and take the intake hose off. Then he took a handful of super fine silica dust, or somthing like that and let it draft up into the intake with it running!
The guy NEVER had a break in problem. I'd like to try that sometime, the expression on the customer's face would be priceless when I told them how I broke in their freshly rebuilt engine.
