Spark Plugs: 41-993 Vs. 41-985

[rngr746]

My 07 4.3L engine has AC-Delco 41-993 (double platinum) plugs as OEM. I have been advised that AC Delco plugs would be the best to run in my truck. I would like to run AC Ddelco Iridium plugs for performance purposes. The only AC Delco iridium plugs I can find are 41-985's and they are not listed as being an applicatioin for my engine. Will they work well in the 4.3L engine? Does any one have any experience with these plugs in the 4.3L engine?

[00Silverado4x4]

Just an opinion but if the truck calls for the 993s why not just run them. My truck has to have the iridiums since it is the flex fuel & I do burn it. What would be the benefit of putting in a different plug? Plus wouldn't the 993s be cheaper than iridium? I'm not sure what performance gains you would get out of the 985s personally so I'll leave that to the experts.