How could air filters possibly change your engines vacuum intake pressure, that's nonsense. the intake vacuum pressure is a direct result of that great big air pump called your internal combustion engine.'The problem is the lack of vacuum because of pod filters.'
That is why one of the forums I read told me to put filter foam in the pods, to slow intake speed. I didn't know about the velocity stacks in the plenum box, but now that I do, I'll try to find some new rubbers and try fitting the box again.
Pod filters are the cheapest, crappiest thing you could put directly onto a carburetor, that is a totally dumb idea and thousands have copied it. On a CV carb it does not work and can not be made to work as good as it should if it has all the parts it needs.