Spark Plug Heat Range

[Stumper]

Spent the last two hours searching the net rying to find a chart that bridges the heat range from racing plugs to standard plugs ... no luck. Looking for some help!!

I have tried running Champion C59YC, C61CX plugs in my car but need to go hotter. I have also run Autolite R3934 and 3935 plugs and still need to be hotter. The Autolite R3935 crosses over to a Champion C63CX or YC plug so going to a Champion 63 series won't do me any good. It looks like Champion has a C65 race plug and then goes into the regular plug series but I can't find a chart that shows the progression. I think a standard Champion 12YC that comes up for a OEM RB motor will be too hot for my motor as it is fairly well modified.
What plugs are colder than the 12YC but hotter than the 63 series (does not need to be Champions)??

I need a 14mm, 3/4" reach, 5/8" hex plug.

 

[HEMI-ITIS]

Here ya go:headbang:

http://www.sparkplugs.com/sparkplug...Interchange+(NGK-Denso-Champion-Bosch)&mfid=0

http://tr6.danielsonfamily.org/spark_plug_heat_range.htm

http://www.autolitecatalog.com/RelatedInfo.aspx?b=A&f=Autolite/ATV.pdf




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That should keep ya busy reading for a while:tongue5:

 

[Stumper]

The first two links I found earlier today. The insert on the Champion plug page showing the new numbers was helpful, thanks.

What I am trying to find is the heat range progression from either a Champion 63 race series up to the 12YC range - or what comes after the Autolite 3835 in hotter range.
After the Champion C63XX does it go to the C7YC and then the C9YC?