· Premium Member
I put Iridium plugs in my '12 2500 work truck with the 345 Hemi about 75,000 miles ago (has 233,000 total). I also put Iridium plugs in my '12 RCSB 345 Hemi about 25,000 miles ago ( has 146,000 total). Both call for copper plugs at 30,000 miles. I don't intend on changing the Iridium till 100,000 as long as I don't have a problem. Nothing fun about changing them so I'm not going to do them for no reason. Been a mechanic for 45 plus years so I've tested a thing or 2.