Spark Plug Question
#6
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#8
If the Iridium plugs are specifically for your engine, they should come factory gapped at 0.040". The TSB from GM (AC-Delco) says the plugs will come factory gapped at 0.040" and to NOT re-gap them. I put some NGK Platinums factory gapped at 0.040" in my LS6 and it runs fine.