Bad experience and other people's story's have made me Anti NGK.
It's the NGK V-Groove Plug's that are Crap. (I don't know about there other plug's) They just don't run great in Ford's for some reason. I work at a Ford Dealership and the tech's refuse to put NGK in any Ford Viechle new or old. Myself personally and buddies of mine also have had bad experiences with NGK. Long Story Short.... I Ran one race with NGK in my circle track car (302) and the car ran like S**T and the plug's fouled up. Threw some Autolite's in her the next day and she purred away and the plug's were nice and tan.... Both plug's were same heat range, same everything.... Stay Away from V Groove's.
Run Motorcraft or Autolite.... nothing else. In a Way You Could Say... Made For Ford's.