Got Shell 93 Octane and now barely idles 1973 Dart 340
Setting has to be determined with testing.
If depressing the throttle is needed when the engine is warm or hot, then that may be an indication that the carb is partly choked, rich, or is leaking fuel.
1) Is the choke plate at the top (the top flap thing) fully opened (vertical) after it has run a few minutes from a cold start in warm weather? When you try a warm restart, pump the accelerator 1/4 and release, and then go look at the choke flap. Is it still open?
2) While idling and fully warmed up, look straight down in the carb throats with a flashlight and see if there is any fuel dripping.
3) Stop the engine and watch and see if any fuel drips down the throats. Open the throttle slowly 1 time all the way and hold it; some fuel will squirt in to the primary throats. Look down into the bottom below the throttle plates and see if there is fuel pooled in the bottom of the manifold.
BTW, this thread may be better restarted over in the Fuel and Air section.