NGK TR55ix Plugs wrong fitment?

[CdnNavybob]

I just took my car (2000 GT) in for its spring maintenance before getting it on the road. One of the things getting done was the plugs, and I had a set of NGK Iridium IX, part number TR55ix, which according to their website is the right plug. According to other posts I found when searching, other people have installed these but my mechanic told me that the thread was wrong on them and they wouldn't fit.

Anybody have any idea why this might be? I doubt he's trying to scam me in any way. He's the go to guy for all the local racers and performance guys and he's pretty much regarded as having one of the best shops in town.

 

[ab 281 gt]

Not sure if the ix makes a difference, but you definitely want TR-55's gapped at .054"

 

[03ghoststang]

thats the right plug i have those installed on my car

 

[Dragstr05]

I just took my car (2000 GT) in for its spring maintenance before getting it on the road. One of the things getting done was the plugs, and I had a set of NGK Iridium IX, part number TR55ix, which according to their website is the right plug. According to other posts I found when searching, other people have installed these but my mechanic told me that the thread was wrong on them and they wouldn't fit.

Anybody have any idea why this might be? I doubt he's trying to scam me in any way. He's the go to guy for all the local racers and performance guys and he's pretty much regarded as having one of the best shops in town.

If you were replacing the stock plugs, this is probably why. The threads on the stock plugs up to a certain model year didnt run the whole way up the plug like most plugs. Ford later updated this to help with the plugs blowing out of the heads issue. I also have a 2000 GT, and after taking my stock plugs out questioned whether or not I had the right plugs, and I was putting in new motorcraft plugs.