iluv2gofast

I went to change out my original spark plugs today with some NGK TR6 plugs, but the threads on the TR6's are twice as long as the originals. I am S/C and I read that the TR6's are the plugs to get. Is anyone using these plugs and ran into the same problem? Are there any clearance issues with the pistons because the plugs are an extra 1/2" into the cylinders?

2VNA

NGK

PART# / HEAT RANGE
TR-55/ 3951/ Stock Heat Range
TR-6/ 4177/ 1 Step Colder
BP7EFS (PN - 3526) BR7EF (PN - 3346) two steps
R5724-8 (PN - 7317) two and a half steps
R5724-9 (PN - 7891) three steps
R5724-10 (PN - 7993) four steps

So you got the TR-6/4177?

iluv2gofast

Yes I got the TR-6/4177

Master

i have them also for my n2O

M1ke

i used these on my gt and noticed the same thing but they will be fine. if the lip is the same distance from the element on both plugs youre fine.

racer02GTstang

i run TR6's with nitrous
i run BR7EF's with boost.

ericdiver

one thing i have learned since i am older than most, is american plugs in american cars and vise vera... they seem to work better for some reason.... fyi, i have autolight copper in mine because of power....i put ngk in my tahoe and it ran funny i switched back to a american plug and it ran better

blueherd02gt

agree totally thats why I still use motorcraft. I tried ngk and had bad luck with em, to each his own

newb2000GT

I didn't look at them because I had a shop install everything. TR6's have been fine so far and no problems on my ProCharged '00 GT.

M1ke

yeah dont worry about it. i put them on my gt right when i bought it and its been fine for the 3000 miles ive driven it. just make sure u gap em right