My VS holley is only opening the secondaries about 1/4 of the way. Will a lighter spring make them open anymore or just make them open faster?
I already went one size lighter, but I think that only makes them open quicker not more.

And before someone says says they only open what they need to.
I wired the secondaried to the primaries to force them open and it likes it much more at WOT which is what you would expect of a big cube motor.

Get a double pumper.................

Well, you certainly know whether the secondaries are open with a double pumper.

But, lighter spring will both open the secondaries quicker and more.

Hot tip: Get the Quick Fuel adjustable secondary housing. It uses a needle valve to control the opening rate of the secondaries. With a light spring, the secondaries will open completely. It's the way vacuum secondaries should work.

Or, get a DP...

Remove the vacuum sec diaphram from the side of the carb.
Test the diaphram for a good seal by depressing the rod while covering the vacuum hole on the housing matting surface. The rod should not depress or undepress as long as your finger is covering the hole. Replace the little cork "O" gasket when you reinstall the vac housing.
the diaphram and the cork "o" gasket have to seal for the vac sec's to work.
Most cars work the best with the standard "plain" spring, the purple spring or one of the yellow springs available.
If the sec throttle plate shafts are binding because of wear , corrosion or a warped carb base the secondaries will not operate properly.