: Spark plugs ??

12-06-08, 05:08 PM
AC plug listings for 6.0L engine show the original platinum tip (AC41-974) and the newer Iridium tip plug (AC 41-985). At about 91K miles I'm about to change plugs - has anyone used the Iridium plugs yet and any issues?

12-07-08, 06:14 PM
I installed the 41-985s. No issues. Just be careful of the gap. The manual says .060" but the plugs come at .040" which is where they are supposed to stay. I guess this plug was designed specifically for this engine and the smaller gap is where it should be. Do some searching on the forum regarding this plug if you're curious. I installed mine with a .060" and then found the posts saying don't change the gap but haven't had any issues with the larger setting. I'll get back in there and change it...umm...when the weather gets warm?? Or whenever I get some free time and there's no good football games on...