NGK 4644 copper core here, I like them better than the autolite

 

i feel like this is the only thing on the truck that you guys have recommended using oem parts to replace oem parts haha

 

NGKs or Champions here. Iridiums seem to run just as good as coppers, and last longer, but are a lot more expensive. Unless your application specifically says platinum (HO motor), I'd stay away from them. Don't conduct as well as iridium or copper.

I am running an experiment for my first plug change. The lower plugs are supposed to be platinums, and I am going to install iridiums. We'll see how it goes.

 

thanks for all the good info, they are getting changed after my vacation to myrtle beach

 

I have the H.O. in my 07, and under the hood it says to use RC12MCC4 Champions, which is not a Platinum? Going to pull a plug and see what is in there and the shape they are in. Truck has 86,000 on her. (Got it Oct. 2011)