Heat soak? Edelbrock carb & air gap
FYI, I used an Edelbrock carb electric fuel pump at the rear of my car. EZ to wire in. Solved all issues of fuel. No regulator needed. My car has a return line which is in use. After I repaired it.
The pump runs slightly quieter with the return line. FWIW.
Oh! And yes, run the thicker carb to intake gasket if possible.