360 running on 4 cylinders

Carb has a low-speed circuit problem , on the side feeding; 2358 runners.
Remember; the carb doesn't suck.
Atmosphere, when allowed into the floatbowl,pushes fuel up the fuel wells, over the top, and into your engine thru appropriate orifices and ports; in response to the reduced pressure at said orifices/ports.

So it needs 3 things; fuel in the bowl, a reduced pressure at the orifice/port, and an unobstructed fuel path.
Air bleeds are installed at various places to break up the fuel into tiny enough droplets so it will catch fire and burn more completely , and to fine tune the strength of the pull-over.

When all-else fails; check and compare the left/right primary throttle valve position, relative to the transfer slot exposure