The carb body is getting too hot. Install a edelbrock wood carb spacer
and block off or restrict the manifold heat riser passages to tame the heat under the plenum.
common issue with edelbrock carbs and aluminum manifolds.
Excess carb heat.
Your local gas station may still be pumping "winter gas"
Winter gas is designed for easy cold weather starting
and tends to vapourize way to easily in warm spring weather.
Creating Hot start issues.