Need help with edelbrock 1406 carb

With your higher 7-8 psi of fuel pressure, set the floats to 1/2" [ not 7/16" ].

You have a flooding issue & it is not due to the 7-8 psi. The needle seats should have a washer under them. Flooding will happen without them. The fuel inlet system on these carbs is very simple....& robust. Binding, leaking floats etc cause flooding. Make sure the floats move freely. Make sure the baffles [ one in the air horn, one in the body ] are not interfering with float movement. Before refitting the air horn & suck on the fuel inlet. If you can suck air, it will flood....