Holley 1920 problem-too rich at idle

Sounds like either the float is stuck or the needle is not seating well. You also may have a crappy gasket on the carb as well. You should not have a continuous dribble that is noticable. It should spray on pressing the gas and on idle maybe some gas should be visible but not alot. I would suggest a rebuild. Kits are pretty cheap and can be had from most shops. As a rule I would stay away from Auto Zone as they dont know 'squat' about older cars. I have decent luck with Napa and the parts IMO are a little better quality. In addition the counter guys know much more about older cars. Good luck!!
Chas.