Thread: Spark plug Reviews

This is some info I tried to compile a while ago.....

97-03 Grand Prix

Manufacturer/Type < < < Colder Stock Hotter > > >


AC Delco

Copper 41-919 41-932 41-921
Platinum
Double Platinum
Iridium 41-985 41-101


Autolite

Copper 104 605 606
Platinum AP606
Double Platinum APP606
Iridium


Bosch

Copper 7580
Platinum 6241
Double Platinum 4304
Iridium


Denso

Copper
Platinum
Double Platinum PT16ETR-L13
Iridium IT16


NGK

Copper TR55
Platinum TR55GP
Double Platinum PTR4B-15
Iridium TR7IX TR6IX TR55IX

Platinum is not recommended for engines with power adders.


Nice info on why to run colder plugs and what it means... Spark Plug Info

webracin

Chis on the NGK, the stock replacement iridium is the TR55IX.

Although you are not supposed to gap iridium plugs here is a how-to for those like me who can't leave good enough alone. Installation Guide: DENSO Iridium