The large screw you have circled is for your fast idle choke speed. The smaller screw above is for your curb idle warm engine speed.
First get engine up to operating temp, then I start with correct what the engine wants timing. After that I will set my idle speed. Then when engine cold and started you can adjust the fast idle screw.
Where is your throttle cable and kick down linkage?
Thermoquad!
Best to search for a 70's style kickdown linkage from carb to trans lever.
Or get a Lokar kickdown cable assembly. I had good luck with those, and easy to install and adjust.