Yeah, I blame the shittastic Edelbrock carb. I had two of them, neither would work worth a **** once hot. The fact that I could pop the top off and watch fuel boil (even after it was cool enough to get under the hood) while it was sitting, even with a spacer (phenolic, wood, didn't matter) was a good indication. Highest temp I recorded was 198F with my ir thermometer on the carb body too. So it's not like I had some nuclear engine or something. The carb just plain did not like heat.
My buddy had a 440, holley, same weather and gas and no trouble. Hence my blaming the carb. He also had an Edelbrock, but it was mounted to an international boat anchor motor which never got that hot under the hood, so it ran fine on that motor.
Once the temps were out of the ridiculous summer highs, the problem literally vanished. The bowls would go empty after parking, but the stalling and bucking and stumbling all cleared up.
I always wanted to try a snokled air cleaner to see if cooler air (versus an open element) would help. My guess is that it would, but I always wanted to go efi anyway and on top of that, even when it ran well the bowls would still empty after parking which made for long cranks which causes me headaches with batteries too (batteries also do not like heat). So in the long run, the instant starting and convenience of efi was a great solution (for ME). I have no doubt the heat could have been dealt with better by using a better carb and adding some cool air.