There are thousands of old Stovebolt engines running around in 90° heat with no issues. I’m not debating if you have a vapor lock or not, but I can see clearly, you may have other issues.
The first clue is you “new” fuel pumps needs an electric backup at times to continue your journey. The quality of these pumps as others on this forum can attest to is “crap”. They have a very high failure rate within the first year. Find an old pump American made pump and either rebuild it or have it rebuilt.
There seems to be an abundance of heat going to your carburetor. Do you have an insulator block between the carb and the manifold? Your fuel line may be routed too close to the block and exhaust manifold. It should pass in front of the block so the fan can help keep it cool before going to the carb.
Do you have a fuel filter in line? Check to see if it is plugged.
What thermostat are you running? You could try running a 160° and see if that helps.
Also check the float level in your carb as it may be too low.
