yes, always check them, way too often at least one or two won't be gapped right, skipping out on the .99 gap tool doesn't make sense

 

The stock gap for a NGK TR6 stock #4177 is 0.039".

http://www.ngk.com/results_cross.asp?pid=4177&x=46&y=11

I ran mine a long time at the stock gap with no ill affects that I could tell. I just had them out recently and they all looked to be burning great. Re-gapped them to 0.035" because everyone seems to run this gap so I thought I would give it a try. No difference that I can tell so far.

 

thanks guys, im going to change them out right now.
ill report back with results.

 

just changed them, the number 6 spark plug was completely split in half.

 

Did the new plugs make a difference or do you think maybe you split it when you took it out?

 

im pretty positive it was split when i put the header on that side, and then when i pulled it out it finally broke the whole way. it doesnt have a big miss like it did have.

 

cool, keep us in the loop. btw, I run the TR6's as well

 

If you really want to find the correct tempature plug for your app. you need to do some plug reads. (http://www.dragstuff.com/techarticle...ead-plugs.html)

I tried a number of plugs doing plug reads and found that the NGK irridum TR8IX gapped to .035 was what my truck needed.
The TR6's just read to hot.

 

Here's another plug thread from the same site

http://www.dragstuff.com/techarticle...ark-plugs.html