Holley/Demon Carb stumble

So what is the 3 or 3d circuit do? seam like its in the dominator carbs more then standard carbs
Mattax, added that to my notes folder.
Intermediate circuits.
Not spent much time learning about them. Used on some Chrysler emissions carbs (Because they ran very lean idle circuits and this let them seperate the transition slot so it had its own circuit).
All I can do here is refer to Tuner. He says the development on Dominators was for independent runner intakes.
Independant Runner intake with Split 4500

3 circuit blocks on 4150