There are some suggested restrictions in the owner's manual. Mostly not to tow for a certain number of miles ( a thousand if memory serves) and not to put your foot in it either. After a lot of reading in Ford truck forums, the advice from the mechanics who tear down engines for a living, was "drive it like you stole it" to set the rings. They claim it is better than taking it easy. And of course, everything you read on the internet is true
. That being said we went to our first Trailmanor Rally with only 400 miles on the truck and although I drive like Mr. Tudball, I did not baby it. Everything has worked perfectly, so from a sample size of one, I don't think you have to worry too much about it. I remember the aforementioned mechanics claiming that manufacturing tolerances are so much better than in the past, that you really don't need to "break in" an engine. Just my two cents worth!