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plugs for 3.4

yzboy85

yzboy85

New member
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
 


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.
 
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 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 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.
 
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