Inconsistent idling problem

davidcribbs said
mguner; I do have an insulator gasket that I run between the carb and manifold. It is the small (maybe 3/8") one that was supplied with the carb. I do have the stock manifolds, but the intake manifold does not seem overly hot. Would I also suffer from vapor lock on a situation like that?

That usually occurs from fuel expansion in the lines and carbs vent easily. A hot carb could transfer heat to the line and cause the fuel between the pump and carb to present a vapor lock type situation but that usually comes from a line routing and or under hood heat issue.