Thread: plugs for 3.4

So I'm planning on doing a 3.4 pulley and header setup next week. I want to make sure which plugs I should be getting. There seems to be some differing information depending on where I look, some places say get tr6s and some say tr55s, so I'm not sure which I should get. Just want to be sure I'm getting the correct plugs

Copper ftw.. I'd stick to autolite 606s

Guess what, this thread will be no different after 10 posts from those other threads or places of infomation.

There will be 3 guys saying 1 thing, 4 guys saying another and so on.

You always want to run the hottest plug you can get away with, plan and simple. So figure anything from a 605 plug to a 104 if it really needs it. Spend 20 bucks and buy 12 plugs and run 1 set and look them over after a few pulls. If they look decent or look bad swap them and do the same thing again. The motor will tell you whats gong on.

I went with autolites in my little rant here, but you can figure out what those heat ranges are for NGK yourself.

104 coppers in my 3.4 set up.

Al 104 coppers for my 3.4" setup

I have found 605's sufficient for the whole 3.8-3.4 range of pullies. Changing from 605's to 104's did not allow me to run any more timing or leaner AFR on a 3.4 ... I don't know of any evidence that colder plugs make a difference at this mod level.

The general consensus to to run 104's, however.

I ran 104s down to a 2.8... 103 on my turbo setup, back up to 104s.. car likes 104s much better than 03s

Originally Posted by adecker

I ran 104s down to a 2.8... 103 on my turbo setup, back up to 104s.. car likes 104s much better than 03s

What issues did you have with the 103s? any? I was about to swap from 104s to 103s this week on my 3.1" M90 pulley setup...

Run 605. I run 104 on my 2.8 setup

I just ordered tr6's but motor is still apart, wont be dropping any pulley sizes till I get an aeroforce scan gauge

I currently run autolight 104s but ngk tr6 plugs and ngk tr55 plugs both seem to give a better idle quality on my friends cars so ill be running them on my next plug change.

Thanks for the input. Probably going to go with TR6s, which are equivalent to AL104s from what I've read, as that seems to be what most are running

I just always stuck with AL's because they're cheaper and they work just as good.

TR6's honestly are too cold for a 3.4" setup.

I'd run 605's gapped at .050" and never look back.

If you're knocking, I'd look elsewhere...as plugs won't fix a knock issue unless they needed replaced.

I've been thinking about trying 103s in mine. Just to see how they look.

Josh run 605's like you should

My 104s look boarder line too hot.

103s worked but it seems to like 104s better

Originally Posted by Iceman6669

My 104s look boarder line too hot.

They aren't I can guarantee you can run 605's just fine.

i pulled my 104's today , they all look new still. like out of the box new.

put the tr6's back in gaped at 60 and 8* of kr lol, the 104's go back in tomorrow with a smaller gap, gonna try 50 or 53, see how it likes it.

Originally Posted by dsmuts

They aren't I can guarantee you can run 605's just fine.

Uh. I think otherwise.