This is about an Edelbrock - the clue is in the thread title.
The secondaries have normal butterflies at the base which should be set by the mechanical linkage to start to open at part throttle and be open all the way at the same stage as the primaries are fully open. It's possible to adjust them on the car but a lot easier on the bench.
For the top secondaries valve there shouldn't be any opening just from the throttle itself but just with the engine off you should be able to swing the valve open all the way easily with your finger (or a screwdriver if your finger is too fat to fit in there). When you let go they should swing back closed from the weight on an AFB style, or there's a little coil spring to do it on the AVS style (which Edelbrock calls the "Thunder series"). The spring type is adjustable for return pressure, the weight type is not.
Knowing exactly what happens to the top valve when driving is a problem. You can't test it just by revving in neutral because the engine just spins up too fast, it needs to be under load.
It has occurred to me in the past that you could maybe simulate driving WOT conditions by sticking a powerful vacuum cleaner up the exhaust pipe - LOL
Might be a giggle to try it; you would have to cap the other pipe if it's a dual system.
AND I should add, only with a dry carburettor, or KABOOM goes the vacuum !
