I think, if I've read right in several threads, when Ford went to the 3 valve heads, that corrected the spark plug problems.
Even way back in the 99 V10, that only had 4 threads in the aluminum heads to hold the plugs in, after many studys, it was found that errors removing & reinstalling the new plugs, was what created the blown out plug problems.
Over torquing the plugs when installing, by hand & not using a torque wrench & not adding a little anti~seize to the plug threads created the most problems.
When you only have 4 good threads in an aluminum head to hold a spark plug in, the highest level of care needs to be taken when rmoving & installing new spark plugs.
Neil