Guys I have a 2001 LS1 with an MS4 Cam, and PRC stage 1 LS6 heads and have a question on the spark plug gap. What should the gap be set too in with a setup like this? What are guys running?

 

32 views and no replies?

 

.035 or .060 depends on the plug. .035 with a plain plug .060 with a platinium. But really i would go with what the manufacturer recomends.

 

As per a GM TSB, 12571164 (AC Delco 41-985) plugs are gapped at .040 when made.

Russ Kemp

 

but before that TSB...the gap was .060

 

True ... but GM changed the gap to 0.040" for some reason. Not sure what it was, but maybe because the OEM coils were being over worked (?).

 

I'm going to go with iridium plugs and need to know what I should gap them too. I'll probably gap them to .040.

 

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.

 

OK. Thanks you guys for your help.