another Carb question

[SS Shaun]

So i am finally getting on my chevelle and having fun with it. So now that i have correct fuel pressure, and the bowls are set and accelerator pump is set no more carb poofs its awesome. So now i am getting on it and opening those vacuum secondaries but here is my question/problem. When i step on it and the secondaries open up i get like a space or a flat spot when those open it up. No miss fire or anything, it seems like it has to catch its breathe and then go. Its like a split second. So a friend of mine helped me install a spring kit setup.

on that spring kit i have a huge amount of springs with colors on it. I put the black spring back in it. So what should i do? Put a different spring in its place? How do i know what spring to use? Do i need a weaker spring or a stiffer spring? trying to learn and figure it out too btw Holley 750 dual feed carb