i am looking for a 5/8 nut on the plug to make it easy to remove because of the headers also for better performance. im running n12yc now and i have no problems [22 runs down the track] looking for any advantage poss. motor is 340 j head 11-1 comp.
what sparkplugs can i use
- Thread starter pat d
- Start date
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dodge freak
Well-Known Member
I would run these, you might want a number 9 heat range==the higher the number the colder the plug http://www.summitracing.com/parts/NGK-7173/
fishy68
Tyr Fryr's Inc.
If you like Champions use a RC9YC or my personal preference is NGK's and the # for them is R5672A-9 for an 11 to 1 engine.
BTW: those N12yc you've got in there now are most likely way too hot for an 11 to 1 engine.
BTW: those N12yc you've got in there now are most likely way too hot for an 11 to 1 engine.
fishy68
Tyr Fryr's Inc.
Pat each application is different. I believe the rule of thumb for power tuning is to start out at .035" and open them up .010" at a time until it misfires then close them back up .005" but I've noticed that if I do that they don't last real long on a street car that gets drove a lot so I open them until it misfires then close them back up .010". If it's a race car that gets the plugs pulled and checked a lot the old rule of thumb should help you make the most power.
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