Stop in for a cup of coffee

Ok guys, I need help wrapping my head around something and I didnt want to make a thread. So explain to me why when you use a carb sizing calculator it gives your what your ideal carb size is.. For example my engine is spec'ed to use a 625cfm carb. Ok now you have a factory 340 six pack and from my research is around 960cfm total.

I was running a 750 on my car and it ran good, but when I threw on a 600cfm carb it was much more responsive..Regardless of that, what I dont understand, how is it possible to oversize a carb?? Why could I not run a 800cfm carb on my car and have it run like a six pack? Is what Im saying making sense?

jetting has a ton to do with that, as does cam keys and accelerator pumps. my 408 believe it or not, also runs better down low with the 600 that's on it, but begs for more CFM over about 4500, which in a truck, I'm never there so I leave the 600 on it.