The EFI myth
With all your issues I think having the fuel supply dead-headed at the carb is the main cause.
This is likely the case with my current engine challenge. Once I have time to turn some wrenches (currently doing two remodels, 1/4 acre market-garden, plus a full-time job) I plan to attempt a return style system. My only hesitation has been that since the fuel is boiling in the bowls, I may still have some issues after shutdown.
I'm not totally familiar with FE engines, and learning more as I go, and it seems they were designed to run at lower temps - so the cooler stat may help. Since I'm inherently lazy, and don't have a lift, that's probably where I'll start. It hasn't caused me any major issues yet, so I've just lived with it for now (plus, it wasn't apparent until a few weeks ago when temps spiked, and we're due for cooler weather again now).
Despite my challenges with this engine, I wouldn't call the EFI on my dart more 'reliable'. It's less hassle, and making changes as conditions vary is much simpler though. But that's only because I've worked past the teething pains of the initial install. I would love to put EFI on this new motor, but with the current heads it's very difficult to keep header gaskets intact, which would wreak havoc with an O2 sensor. Something I've found EFI cannot tolerate.
once I park somewhere after the engine gets to operating temp I open the hood about 1/4-1/3 of the way to let the hot air escape
I do this frequently - open the hood. It does help, and I agree it helps prevent that crank-crank-crank-I-hope-it-starts situation.