Percolation? Heat soak? Don't drive during summer??

None of those are anywhere near me. :(

Nevermind. I see he beat me to it. I don't know what to tell you. I drive three old carbureted vehicles in the HOT HUMID GEORGIA summer and they don't do anything stupid. So I guess you can whine about something not being near you, OR you can take a drive, get some non ethanol gas and TRY it and see if it makes a difference. I have non ethanol gas all around me, but I don't use it. All my junk runs good on 10% ethanol. That's another thing to consider. What % of ethanol does the gas out there have? Different locations can have different amounts. Here, we have a maximum of 10%. My slant six Valiant runs dang good on it. If there was a car that'd exhibit vapor lock, that'd be it. The fuel line runs right up against the bottom radiator hose, around in front of the engine, then turns parallel with the vehicle center line to the carburetor. It runs right over the intake and exhaust manifolds where it;s subjected to some HOT temperatures and I have ZERO issues. I also am runnin the THICK (over 1/4") base plate insulator gasket.