Holley Idle mixture screws non responsive?

I scooped up a complete 383 which the owner knew nothing about other than it was rebuilt before he got it and ran great when pulled. I since have changed the intake to a performer RPM 383, with a new 750 vacuum sec, 4160 holley. While I had the intake off I checked out the cam and I believe it to be the mopar purple 484 shaft, I checked the timing chain and the cam was installed straight up (no advance), I calculated the compression a little over 9:1. The cylinders still had the cross hatching on them. So all in all the motor looked great.

I have it running.. but there are a few minor issues. One the idle mixture screws are non responsive. no matter where they are.. they don't really change the rpm or vacuum reading. If I turn them in they will kill the motor thats about it.

Also, the vacuum is about 11-12 psi in park, and about 7-8 in drive. Is this normal for this cam? I thought there would be more vacuum, so I have taken the intake off 3 times now and redone the gasket. The vacuum is always the same.

I changed the power valve to a 3.5 since I had one.. no change.

I have set my timing about 14 degrees, plus the mechanical and vacauum advance in the distributor.

So any ideas why the idle mixture screws don't do anything? And also does this vacuum reading sound about right for this combo??

Thanks Bryan