Percolation? Heat soak? Don't drive during summer??

I can't believe how many utterly nonsense, nincompoop answers you've gotten... While unbelievable still believable...
Let me expel some of these phenomenally incompetent responses...
First it has nothing to do with if it's a Holley carburetor and Edelbrock carburetor or anything like that... And buying a $2,000 EFI kit to solve this problem is utter nonsense..
Anybody who has to have an Edelbrock installed.. then take it to a mechanic who can't make it leaner by changing metering rods or jets has the wrong mechanic especially if that mechanic has to send it to a carburetor Guru...
What kind of gas you put in there whether it's ethanol or non ethanol ain't going to make a flying scrap of difference...
If your carburetor was emptying out when you hit the throttle and that steam comes out of there that's like said vapor from there being fuel in the carburetor and the accelerator pump squirting it out onto the hot manifold creating vapor type steam.
If it's a clogged fuel line or fuel pump that's not working you should be able to throw a little splash of gas in the carburetor after it dies and it should fire right back up at least momentarily while that little bit of gas you put in there is burning...
If all that settled its electrical... and definitely not your plugs or wires unless your plugs got totally fouled and your wires got burnt through... Which is still electrical..
I'm liking the ballast resistor theory because at worst case scenario it's only five or six bucks and you should have a spare in your glove box anyways... Cheaper than two spark plugs...

I had a 318 with headers, cam, similar carb and lived in his same city and had very similar issues. No manner of metering rod, jet, or fuel pump changes ever fixed it either. Efi with high pressure fuel delivery did. I found the Edelbrock carbs to quite temperature sensitive and tracked everything with a wbo2 and ir thermometer. I'm not recommending doc go to efi, I'm fact I recommend against it (and said as much), but no matter what I did I could never get rid of the heat related issues with that damn Edelbrock carb. My buddy who's into e bodies always ran holley and never had a single issue... So that's where my experience comes from.

Living with a hot rod in the southwest is a completely different animal than in most places. Hard to believe but true.