Automatic Idle Adjustment One Person HOW?

340inabbody said
“I also run an idle solenoid so that I can set my in D idle rpms differently than my N/P idle rpms. I like to keep my N/P idle rpms lower than my in D idle rpms”

What is an idle solenoid? When I drop into gear and it’s under load I always drop RPM’s. This is fundamentally why I started this thread. You seem to be able to avoid this and I want to understand how….

The one that I use is the Holley Idle Solenoid #46-74, and the bracket #20-9. Here are a couple of reference pictures.
When it is extended, then you can adjust the head head tip to achieve your higher idle rpms. When it is retracted, then you rely on your carb idle screw for the idle rpms.