Spark plug question

I have a 1967 Dodge Dart GT with a 273 4 bbl and 318 heads. I'm upgrading to Petronix Ignitor II electronic ignition and Flame-Thrower II coil.
My question is, what plugs do y'all recommend and what gap?
I am thinking Champion RN12YC set at .040.

Due to the stupifying down of Google, I can not find an application chart for Champion anymore, that lists anything except their gold/ platinum plated specials. Anyhow, I would not gap them more than .040, and would probably just gap them at .035--original specs

I did not realize 273's took that hot a plug?