69 340 AVS fuel leak

I had it rebuilt by a very reputable local shop. He has attempted several times to adjust the floats and the baffles.

I dont understand why it doesn't leak while running, only after I shut it down. If the needle & seats weren't correct, you would think it would leak all the time.

The driver side has a vent opening, what vents the passenger side? That is the only side that leaks.