autolight, spark, plug heat ranges

[old31]

I am currently running auto light 66 plugs having a difficult time trying to find the next hotter plug.

Does anyone have the number for the next hotter plug or a comparable with champion or something else?

Talking with the parts companies, I might as well be talking with a tree.

[Gary WA]

The higher the number of plug the hotter.

[old31]

According to auto lite directly, they told me that the 66 is the hottest plug that they have.

I can’t read read the above chart does anyone know what another brand plug equivalent to the 66 will be for the next step hotter?

[Y-Blockhead]

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Nice chart Gary. I don't see Autolite 66 even listed?

I run W-18 Champion, according to the chart between W-16Y and 3X.

Ford garage does not mention Autolite 66 plugs either. http://www.fordgarage.com/pages/brum...kplugnotes.htm

My plugs after round trip to OC pancake breakfast, ~75 miles.