Resurrecting this old thread. Funny, I am just now getting around to doing my plug and wire job.
Everything I am seeing says .040, the plugs are pre-gapped at .040, the RA and other websites say .040.
The new 41-962 plugs I got from RA are pre-gapped at .040
With tons of research and looking at TSB's it seems like the only discussion regarding gap change from .060 to .040 is regarding the use of Iridium plugs, but that does not explain why the platinums are pre-gapped to .040
I pulled an original plug (at least what was in there when I bought it at 66k miles. I now have 204k miles on it.)
The plug I pulled is NGK PZTR5A-15 AC Delco 12567759 which appears to be a platinum plug.
With my 138k miles, the original plug that I pulled has a gap of .062
I am wondering if these old plugs were originally installed with the .040 gap and they have worn to .062, or is it possible that after more than 138k miles that they have only worn .002 if they were previously installed at .060?
I am on the fence here about what to do. I would be fine using the double platinums if I can get the gap set with confidence, since it seems like my original platinums have served me well for at least 138k miles.
I can get 41-110 on Amazon for 7.00 with free shipping (but amazon fitments says it does not fit my Suburban though) and know the gap is supposed to be .040, but that seems like a waste.