Float is set too high and fuel pressure may be excessive. Those carbs will only tolerate about 5 psi at the inlet before the pressure unloads the needle and seat and the pump begins to blow raw fuel into the intake manifold.
Tee off at the carb inlet and run a small copper line back to the firewall, then up past the hood lip and out to the grillework in front of the windshield. Temporarily mount, with duct tape and tie wraps, a 0-15 psi, mechanical, liquid-filled fuel pressure gauge on the grillework in front of the windshield so that you can monitor the pressure as you drive. Fuel pressure regulators will work ok on an electric fuel pump, but don't work so well on a standard cam-driven mechanical pump. If you have excessive pressure and are using a mechanical pump, the fix is to replace the pump with a plain, simple Carter pump for your OEM application. Google for 5 psi fuel pump.