Ac Delco Double Platinum or AC Delco Iridium
 

So, after a long battle with my rough idle problem, I decided to break down and buy a new distributor cap and rotor. OH MY GOODNESS! I know everyone says to use AC Delco parts for the secondary ignition system but OH MY GOODNESS I will never doubt the experts again. As soon as I switched out just those two parts, my idle when from rough to almost completely smooth!

No, I'm not an auto parts salesmen nor do I represent AC Delco in any shape, form or fashion. But I can say this, if ANY ONE ever doubts the experts on this forum, take another look at yourself and ask the question "why doubt them?" Seriously! I know we have all been burned a time or too and for some of use it may have been one too many times but please, take it from someone who questions just about everything - DON'T BUY ANYTHING ELSE OTHER THAN AC DELCO SECONDARY IGNITION PARTS! Or, at least DON'T go cheap on the distributor cap and rotor!

Now, as some of you know, I did change out the plugs but I replaced them with Autolite Platinums. My question is this, Autozone has AC Delco Dbl Plat. and AC Delco Iridium's for the same price. The heat range for the double platinum is a 3 with a thread depth of .679" while the iridium has a heat number of 4 with a thread depth of .689". Which one would be better for the engine?

Thanks again you unpaid professionals. I've definitely learned a lesson in honesty from this forum!

Find the heat range of a stock plug & get the ones that are closest to that. You don't want it running hotter (these run hot enough) & cooler may cause carbon fouling from incomplete burns. Unless you have modified the engine IE: forced induction, then run a 2 degree colder plug.

AC Delco 41-993 with a gap of .060" that's what came in it new, that's what they run best with.

As I copy & paste that to a notepad file for future refference. ;-)