Spark Plugs for Aluminum Heads

[matt63]

I'm wondering if a hotter plug is required when using aluminum heads.  If the heads get rid of heat faster does this effectively cool the plugs more than with a cast iron head?  Perhaps I'm over analyzing this. Anybody got aluminum heads and have a plug number they might recommend as a starting point?

[matt63]

I asked my engine builder about this today and he said that the head material doesn't affect plug selection.

[Dragula]

He is correct. The only thing you want to use for selecting the temp range is compression. I have a baseline chart on my home computer, but the higher the compression, the colder the plug.

[Dragula]

Here's the chart

[matt63]

Thanks Dragula.  I haven't seen that chart before.