NGK Racing Plugs question

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sverbus
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NGK Racing Plugs question

#1 Post by sverbus » Mon Jun 04, 2012 10:22 pm

Quick question about some thoughts on what head-range plug to run...

remember, 15.2:1 compression...112 octane fuel.
Pro-1 230 heads worked and opened up. 950 4150 style carb

When i ran the car 2yr's ago I was running the NGK racing plug -7's...that's a medium/hot range plug. With that kind of compression, I know you keep a pretty small gap, typically around .020 correct? would any of you change the heat range? I honestly don't remember how they looked 2yr's ago when I ran the car.

If any one needs additional information to help answer this, just post here and I'll hook it up.

thank you,

Scott
'70 Nova
434 small block
Best so far of 10.51 @ 131mph with a best so far 60' /1.46

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John_Heard
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Re: NGK Racing Plugs question

#2 Post by John_Heard » Tue Jun 05, 2012 7:38 am

The 7's are a decent plug if you want to drive it around town and still keep them clean. If you think they are a bit hot, you could move to the -8's for a cooler plug for racing.

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sverbus
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Re: NGK Racing Plugs question

#3 Post by sverbus » Wed Jun 06, 2012 1:55 pm

Thanks John for the info...1 more question though...is a cooler plug better for engines that will see above 7000rpm?

Thanks
'70 Nova
434 small block
Best so far of 10.51 @ 131mph with a best so far 60' /1.46

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John_Heard
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Re: NGK Racing Plugs question

#4 Post by John_Heard » Wed Jun 06, 2012 2:14 pm

I'm not too sure that RPM has a lot to do with this, it's more to do with Cylinder temperatures, more power needs a colder plug. But, if you're driving around town with it, cold plugs will foul out very fast idling around.

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Moparious Maximus
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Re: NGK Racing Plugs question

#5 Post by Moparious Maximus » Mon Jun 25, 2012 5:53 pm

I used to use -7's, when it was a carbed gas motor, still used them when I went alky. Now with the blower motor I went to -9's.
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jmarkaudio
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Re: NGK Racing Plugs question

#6 Post by jmarkaudio » Tue Jun 26, 2012 3:08 pm

8's will be fine if the idle and transition circuits are tuned to the lean side, this will keep the plugs clean enough. We run 7's up to about 14.5 to 1, my 15.5 to 1 SB2 uses 8's.
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