i've run into a couple 03 super duties with the newer heads but never a half ton yet.

 

Well, I guess I don't know for sure that my truck has the upgraded heads; I went from a lot of posts stating the '03's had the upgraded heads and was also judging from when I put in the new plugs - felt like there were more threads! Maybe one day if I'm bored or insanely curious I'll remove one from #1 or #5 and see if I can actually verify, unless there's an easier way...

My plugs had a lot of carbon on them and gunk/dirt. I think when the shop put them in, they did absolutely NOTHING to clean the dirt that accumulated in the plug well and just shoved the plugs down there. There was a fair amount of dirt in the wells when I finally took to doing the work myself. Takes a few extra minutes to blow out the wells then shove a rag down there to get any residue... pathetic workmanship. I'll have to post a picture of the plugs. I believe it was cylinder #6 that had the plug that was finger-tight.