Slant 6- Idle and Running

The 1920 has a weird economizer block in the fuel bowl that can get plugged up. Take it out and soak it and hi the passages with air to clean them out. I bet its there. Part #44. Also check the throttle shaft for wear. The accelerator pump sort of works backwards on that economizer plate and if it has a leak, it will weep fuel out the linkage or worse, a small hole that will shoot fuel onto your intake.
Holley1920CarburetorExplodedDiagram.jpg