I have the "ReadyLift" leveling kit on my '06 6.0L 4x4. The instructions say in order to clear 35"s you need to make a bracket which pulls the plastic inner wheel well. I have not yet tried to put 35s on it, but I'll let you know when I do.
Link:
2005-2009 Ford F350 Super Duty 2.5" ReadyLift Leveling Kit system