Gas Tank

Ok now its starting to sound like a candidate for getting pulled and looked at.

If the problem you're describing is in fact vapor lock, it unlikely has anything to do with the gas tank. There are mods such as running a fuel injection type rubber hose from the fuel pump to the carb that can fix or help that. Mine used to not want to start on hot days after being driven and then started up in between a half hour or so. Replaced the metal line with a rubber hose and now the gas doesn't get as hot and I haven't had that problem in years.

When buying a car that hasn't been driven for any decent amount of time, one of the first things you want to do before running the motor is pull the tank and make sure it's not rusty or has varnished gas inside. You don't want any of that crud getting into your carb and engine.