The preference depends on mods. Many of the more modded cars are running one range colder plug to compensate for the heat the mods are causing.

I'm not modded on my 97 and it runs great. My 95 has a pulley and CAI but that is still minor and the iridiums are in that as well.

I picked up the AutoLite 104'* today, the guy at Autozone didn't understand why I wanted to drop a heat range at first. But he even went out of his way for no reason to double check that 104 was one heat range colder even though I knew by now it was.

Irridium or Platinum? Which is it? Platinum plugs are not for Supercharged, Turbo, or NOS cars.

my mistake its 1.19 they are on sell

According to the site below, the plugs will interchange. When you access the site you will have to click on "Vehicle List by Part Number", and then put in the # 41-101, and it will tell you all the cars that it fits.

Iridium Spark Plugs Replace Platnium

GM has come out with their own iridium spark plugs. As of 2003, the new 3.8L and 3.4L come standard with these plugs. In addition, if you try to buy the original platinum plugs for a 2000-2002 3.8L, the GM system changes the number to the new Iridium plug stock number. They are also right around the same price as the platinums. It is unknown if the older 3.4L will accept the Iridium plugs or not. The GM number is: 12568387. The AC Delco number is: 41-101. What'* the difference? Go to Sparkplugs.com, scroll down and click on the "iridium" link under "Precious Metal Types".


http://www.acdelco.com/html/catalog/index.htm

edit, you have to go to plug 411 to get to precious metal types

Sonoma, if you run Platinum plugs in your Supercharged car, you will have problems. NGK, the manufacturer of AC Delco plugs, told me that personally on the phone, backing up what we already know from experience on this forum.

Do NOT run Platinum plugs on a Supercharged car. Irridiums are fine, but not Plats. They will interchange in MOST cars, but not yours.

More details in Techinfo if you're interested.

The dude at napa said platinum (my bad for typing out the word platinum). They are iridiums, so they are not platinums.

well go for it then

Be careful out there.

Big difference, and a waste of money when you have to change out Plats in a month for Irridiums.

Copper plugs are preferred over Irridiums in Supercharged cars. They dissipate heat more quickly.

NGK TR55 gapped at .055" for one heatrange colder
NGK TR6 gapped at .050" for 2 heatranges colder

Or the Autolite plugs (copper).

Stinkin Napa dudes...More misinformation from Napa!!!