Fastlsvette

can anyone tell me the best spark plug and gap to use?

maxx2200

Lot's of reading on this subject. You certainly can't go wrong with factory recommendations with a stock/mildly modded daily driver.
I just installed NGK TR55's gapped at .060

dblerman

Also note that there was a TSB on the new AC Delco iridium plugs get gapped to .040

Fastlsvette

yeah i was going to get the TR55s just wanted to know if their was another alternative thanks

Cybermind

I highly recommend the NGK IX Iridium plugs. Keep in mind that if you decide to get Iridium type plugs, you do not gap them. You can damage the tiny iridium electrodes by doing so. You are required to leave them at factory set gaps.

Conventional plugs will definitely require gapping.

Vetteman Jack

I am running the AC Delco Iridium plugs - works very well for me. The NGK TR55s are also a very good plug.

LoneStarFRC

Several good choices out there and by picking an iridium or platinum plug from any one of the major brands, you can't go wrong. Iridium and/or platinum plugs have a longer life span overall than conventional plugs, thus the premium price.

No need to worship at the altar of a conventional NGK (who also make iridium plugs) as many seem to do these days.

HTH

leadfoot4

Despite the fact that nobody here really cares for them, I've had Bosch Platinum +4s in my car for a long time, with good performance.

hamhead

I have, and never have had, a problem with cheap old copper plugs. In fact, I've seen more often than not misfires on the dyno on relatively new platinum/iridium plugs that end up being corrected by running a cheaper copper plug in its place.

There is no point, in my opinion, in getting more expensive platinum or iridium plugs if you don't mind getting dirty and doing your own maintenence.

mrm1149

AC Delco Irridiums, competitively priced also

sircampsalot2

I just installed NKG's coppers in mine and it seems to have lost power from the ones i had in it before...I did gap them at 45 and am wondering if i should regap them to .60 someone on here told me the .60 was too much of a gap and that it should be between 40 and 50 so now im confused

ZeeOSix

Everyone who makes spark plugs (NGK, AC Delco, etc) for the LS1/LS6 (and many other GM engines) will show them to require a gap of 0.040" due to this TSB which was put out in Dec 2003.

http://www.acdelcotechconnect.com/pd..._03D-J-171.pdf

I think I've posted this TSB in ever spark plug thread that's popped up in the last 2 years.

mobius

Br7ef @ .024

Mickeyrx70

AC Delco Iridium now; Bosch +2 Iridium previously. Both are good.

racebum

you did lose power but it's a very small amount, would guess under 5hp

the larger the gap the more power the engine will make

but

it also increases your risk of detonation as the gap increases. think of it similar to advancing ignition timing.

.040 is safer. many, many ways to make power with these engines. why risk it?