Vapor lock- additive?

Well most of us are running mechanical pumps…

And mechanical pumps are usually worse off in this metric since they put way more heat into the fuel than an electric pump.

But to be honest I don’t think it’s a big problem either way. If you have an intake with the exhaust crossover blocked and are running a carb spacer the fuel stays pretty cold. I always have fuel in the bowls of my aluminum holley for up to a week