I have a holley 750, vacuum secondaries.........is there any way to tell if the secondaries are opening? Would it be really obvious if they weren't?

thanks

 

Hard to tell if they are working properly. You shouldn't be able to feel them open. I usually wire them shut and make a run (and/or disconnect the arm from the vacuum chamber). If it noticably struggles in the upper RPMs it means they were opening before.

 

You can actually put a light paper clip on the rod from the secondary diaphram. If they open (rod pulls up) it will move the paper clip.