plugs for 3.4

**yzboy85** · 10-05-2014

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

**REDCRAPGP** · 10-05-2014

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

**Fivefingerdeathpunch** · 10-05-2014

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.

**Scottydoggs** · 10-05-2014

104 coppers in my 3.4 set up.

**Iceman6669** · 10-05-2014

Al 104 coppers for my 3.4" setup

**Impala131** · 10-05-2014

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.

**ADrugDealer** · 10-05-2014

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

**97AutoXVette** · 10-05-2014

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...

**dsmuts** · 10-06-2014

Run 605. I run 104 on my 2.8 setup

**Trett93** · 10-06-2014

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

**Frosty** · 10-06-2014

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.

**yzboy85** · 10-06-2014

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

**blueguy** · 10-07-2014

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.

**Iceman6669** · 10-07-2014

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

**dsmuts** · 10-07-2014

Josh run 605's like you should

**Iceman6669** · 10-07-2014

My 104s look boarder line too hot.

**ADrugDealer** · 10-07-2014

103s worked but it seems to like 104s better

**dsmuts** · 10-07-2014

Originally Posted by Iceman6669

My 104s look boarder line too hot.

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

**Scottydoggs** · 10-07-2014

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.