Percolation? Heat soak? Don't drive during summer??
Here let me make some sense of why I think this is utterly ridiculous. So what you're telling me is if you had this car before the invention of EFI for aftermarket you would have never been able to get the car running correct? So back in the seventies and before fuel injection was widely used people couldn't run their cars in the southwest without trouble?...
Remindeds me of when I had a warehouse job about 15 years ago and drove my duster to work in the snow and I had people ask me how I drove that thing in the snow to work because it didn't have front-wheel drive or whatever like modern cars? I said what did you think they did in 1972 not go to work because it was snowing?...
Likely your car running good had absolutely nothing to do with the EFI you put on there but something to do with either another part you change while you were doing that or maybe just a bad ground on the ignition system that was accidentally fixed...
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.
