Carb Help

[jewing3886]

I have a 66 c10 new 350 crate engine stock. The problem is shut it off for over 10 min before restart. It spins over a lot before it cranks carb is flooding. It had a new eldebrock I thought the carb was bad traded it for a new Holley same problem. Ive tried a regulator a fuel pump carb spacer still no difference. The fuel pressure in the line rises after shut off I notice this buy taking the fuel line lose at the carb. Fuel was shooting out like a rocket. Any help please driving me crazy ps my fuel pump just has an inlet and outlet no return.