adamgl

I've done some research and most ppl seem to say use stock plugs.

What are you guys with 550 RWHP - 600 RWHP Machined heads, cam and headers running?

My car had NGK R V power TR5's in it ?!

And they recommend TR6's for stock. Why would someone with 100hp over stock go to a higher heat range instead of colder? Makes no sense to me.

Buddy A

I got a small cam and put down 571/542 and tuner installed NGK TR6

adamgl

Maybe I shoulda put something about valves in my topic title to get more responses, lol.

FNBADAZ06

Unless you're experinecing detonation, going N2O or forced induction, I don't see why you would change from the stock plug heat range recommendation. Are your heads milled to up your compression ?

I switched to the new TR6iX iridium plug......same heat range just a different conductor.

adamgl

Milled to 11.5 : 1 and I only have 91 octane where I'm at.

When I bought it, the plugs where TR5's. Just makes no sense why they would have put in a hotter plug than stock?

My tuner said he couldn't put much timing in it. Maybe the "too hot" plugs made it knock sooner than the recommended TR6's would?

VetteVinnie

NGK TR6, although I'm tempted to change to iridium TR7 for the summer.

FNBADAZ06

Yeah.....why would someone put in a TR5 ?
I'd go back to the stock plug temp and see what happens.
I'm approx 11.5 and 91 as well, though I'm currently running the corn juice. I'm on NGK TR6iX's, which is their new iridium plug. I got them on a miss marked advertisement last year on Sear's website (of all places ), or I'd be running on the OEM Delco's.

Unless you need to pull some heat out of the combustion chamber, I see no real reason to change plug temps.