best plugs for our 5.9L
Site Moderator
Joined: Jan 2008
Posts: 8,374
Likes: 28
From: Sioux Falls, SD
Like I said before, the Mopar plugs are the same as Champions. RC12LC4 is the number. These are the same plugs that my truck left Saltillo with. Check the emissions label on yours for the correct plug # and gap. I got 8 at Advance Auto Parts for $15. My truck really likes them compared to the Autolite 3923s and Bosch +2 plugs. When I change my plenum gasket, I'm gonna switch to some NGK V-Power plugs.
Also, if your truck does not like the 3923s, try some Champion RC11YC plugs. They are the same (colder) heat range as the 3923s. I'm looking for an NGK cross refrence.
My truck liked to occasionally ping at WOT with the V-powers, but otherwise, they were good plugs. It may have just been the Superchips tuner, I don't know. We'll see after I get the truck back from the body shop (Monday) and program it with the SCT.
According to several parts websites, the stock heat range NGKs are the ZFR6F11 plugs. That would mean, since the higher the number the colder the plug for NGKs (silly Japanese manufacturers), the next heat range colder would be ZFR7F11.
According to several parts websites, the stock heat range NGKs are the ZFR6F11 plugs. That would mean, since the higher the number the colder the plug for NGKs (silly Japanese manufacturers), the next heat range colder would be ZFR7F11.
