no, no you are right. sorry about that, i'm horrible at English!

any and every carb will only flow what the engine needs. a 1000cfm carb on an engine that can only flow 500 will only flow 500 with the throttle wide open. for example, your 351 will have to spin faster than 6000rpm in order to flow 600cfm.

that little holley 500 I had just flowed way more fuel than it should have through the idle circuit.

the problem with a bigger carb is that it doesn't flow that strong. there is so much more area that the same amount of air is flowing through, that air is moving alot slower. if the air is moving too slow, the carburetor can't meter the fuel well enough.

on another note, have you ever drove a vehicle with a really touchy throttle? a smaller carb (or smaller primaries) is less likely to be like that.

i'm not sure if that was any better in all honesty...

don't worry about being young, its just good that your asking questions. i'm actually probably not much older!