Spark plug gaps

go-fish said
I don’t know much but I’ve got my carb tuned pretty good with the help of a good friend.
@RustyRatRod I had a set of plugs in the 340 when I got the non-running car. Engine was freshened by the previous owner but never ran. I started the engine with new plugs, the #4 autolites.
My limited knowledge was leading me to a colder plug for open chamber heads and lower compression. Am I off base here?

I’ll get a plug from each bank and read those when the ice thaws here.

You have it backwards as a rule of thumb. Normally more compression will tend to need a colder plug. More compression = more heat and in order to keep that heat in check, you will want a colder plug. But I always go by the "how it runs" and how the plugs look" deal, because there are exceptions to every rule.