340 with edelbrock heads overheating

StreetSleeper said
Rusty I have a couple of questions about this.
Generically, would 12 degrees of initial timing be about right?

Second, if he has closed chambered heads, wouldn’t those be more efficient and need less timing? Initial or total?

He didn’t mention if he has 340-specific-edelbrock open chamber heads.

Does the aluminum affect timing?

I would have thought more efficient heads need less timing. Thanks for your wisdom!!

@RustyRatRod

Oh and as for the 12 degrees, I would consider that low initial timing for any type of performance engine. Generally speaking, you concern yourself more with total and WHEN (at what RPM) you achieve total. I would consider "around" 16 degrees initial a "starting point" for any type of performance build, regardless of compression or cylinder pressure.