pacorocco6

Confused about which one to use on my 01 Z28. I know the 41-110's are iridium and the 41-962's are double platinum. There's a GM tech bulletin saying 06 and older lsx's are to use 962's but I don't know why. What is the general consensus on which to use? Getting ready to do a LT header install & figured I'd change the plugs since the 2015 acdelco plug rebate is in effect.

high n dry

iTrader: (18)

Don't use either! NGK TR55 is what's been proven time n time again to work better than stockers...

5550racing

My car did not like the smaller gap that the AC Delco recommended plugs come with. Maybe they would have worked better with a larger gap, but I was told not to change it. I ended up taking the AC Delco's out after a couple of days and rolling in a new set of TR55IX's gapped at .065. I had NGK TR55IX previously and they were great. My 2000 LS1 says gap the plugs at .065 in the manual and I trust that over everything else I've read on the internet.

dailydriver

True, but some of us with mostly stock LS1s put MANY daily driven miles on them every year.
The Iridium plugs, especially the 100K mile rated variety, make doing the time consuming (and yes, I know some on here claim to be able to do it in < 1/2 hour, but I DO NOT believe them!), PIA job of changing out the copper tipped plugs every 30K miles or less, a MUCH less frequent maintenance item, especially on fourth gen LS1s that still have ALL of the emissions equipment!
This is despite so many on here claiming the TR55s perform so much better, especially in modded engines.

$750 L98

iTrader: (7)

I used the NGK TR5IX plugs, 7397 is the part number. I have them on a tuned 2002 Z28 with around 150k miles on it now. They work great. I've replaced more than one set of TR55 plugs that were left in the motor by the previous owner for far too long - likely because they didn't feel like changing them again.

If you want a good long life plugs, the TR5IX is it.

RPM WS6

iTrader: (3)

You can use either. The bulletin you're referring to (13D-070) indicates that the 41-962 platinum plugs are less expensive for the older applications and were intended to keep ACDelco competitive in that market. Both plugs are correct and either can be used, the iridum tip was the recommended service replacement for LS1 engines prior to the re-release of the cheaper platinum plug, so you can use either.

Factory recommended gapping was .060", not .065". That was for the original platinum tips.

I've used the 41-110 gapped at .040" myself, and had no issues with them at all. You are correct that ACDelco recommends not re-gapping the iridium tips from their production spec of .040".