carb spacers???
So park it with t he hood open to see if it makes a difference. If this helps you have a heat-soak problem. The 1406 I had on my Wagoneer suffered badly until I put an isolator under it. An electric fuel pump helped a lot as well.
We've gotten spoiled with fuel injection in our modern rides and forgotten how miserable carbs were. Also, current gas like E10 boils at a lower temp. Not an issue with high pressure EFI, but hot restarts with carbs can be a pain.