69 340 AVS fuel leak

My 69 Dart Swinger 340 has been leaking fuel down the secondaries after shutting off the engine while hot. It's got a new fuel tank, sending unit, I cleaned out the fuel tank vent tube, new NAPA fuel pump, filter, and a recent rebuilt to the original Carter AVS.

The motor is the original 69 340 X head, with a slight increase to the cam. All original manifolds, exhaust, etc. While running, there are no leaks, the car runs great. About 30 seconds after shutting off the engine, fuel begins to drip from the passenger side tube above the secondary throttle butterfly. There is a gurgling sound from the carb while this occurs.This continues for 5 - 10 minutes and floods the motor, making a hot restart difficult. Outside temps are only 20 - 40 degrees, motor runs at proper temperature. If I loosen the fuel inlet nut at the carb, The gurgling and dripping stop.

With the throttle closed, the vent cap on the drivers side of the carb opens as it should.

The floats have been adjusted to several different levels, this does not help, and they are currently set to the factory specs.

Removing the gas cap does not help either.

Any ideas?