on a 6.0 I wouldn't run it pat about 50%, we have a guy at work who has been running it in his four about 5 months and hasn't had any problems except when he goes to about 70%. he filters it out several times before he puts it in his tank, and we change the fuel filters every oil change just to be safe, low fuel pressure will destroy the injectors so better safe than sorry.
I can't imagine what the long ill effects on the injectors would be,
I wouldn't run it, not to mention if you ever go somewhere and get your fuel tank dipped you might get a pucker factor when the guy dipping your tank notices it's red.
6.9/7.3, you can run it all day long. Just add some cetane booster in with it. It will start to smoke more but so. 6.0, has to many sensors and the injectors do not like it. 6.4, dont even think about it.