You're right, it doesn't make sense. It wasn't part of the original data that it was fine before (I misremembered the header/manifold situation).
I just know I struggled massively with heat issues when I was still in Vegas, so I relate to his situation. I tried literally everything (heat shielded gas lines, Re routes fuel lines, spacers, hear shield under the carb, and even a return fuel filter) and it still had massive problems until the weather turned each year (while my holley running buddy had zero issues all summer long... Drove me nuts!). I share that info to dispel the idea that a heat shield or spacer will help much, because neither did anything for me in the same situation. The thing that made the biggest difference for me was a new clutch and fan, but it wasn't a 100% fix either. The return filter helped some, but fuel would still boil in the lines/filter after shutting down and heat soaked. Hell, I could hardly be under the hood right away after shutting it down. Even in our air conditioned warehouse where I stored it every weekend. I also tweaked timing all over, jetting, rods, springs, fuel pressures, you name it. As soon as the highs dropped to the low 80s it was fine.
But there's more to
@DentalDart's story than I remembered, and it points at electronics. The fuel squirt idea is a great suggestion in any case and will certainly rule in or out the notion of vapor lock. But since it was fine before, I doubt vapor lock is the root cause.
