Bring it to my place and we can spend a day getting it dialed in. IIRC, that carb is a Holley 390 (correct me of I'm wrong Gary. The first place to start is to get the idle circuit dialed in. The main jets do nothing at low RPM. The power valve should also not be in play here. We can install a power valve plug to eliminate it as a variable if needed.
Getting the idle tuned involved getting the idle jets dialed in. Start with the idle screws and tune to best vacuum. The idle RPM will change. Readjust it to a reasonable setting. Now don't assume that we're done with idle at this point. If the idle mix screws are out too much or in too far, you need to adjust the IFR (idle feed restrictor) and IAB (idle air bleed). The IFR is basically a jet for the idle circuit. It can and needs to be sized larger or smaller to get the idle mix screws in the sweet spot. I have all the tools and most of the parts to make these changes and can do it at my place to bring them anywhere.
Once idle is done, we can look at the main circuits. This involved playing with the main jets (how much fuel) and the HSAB (high speed air bleeds) to determine when the mains come active.
There seems to be a lot of voodo when it comes to carb tuning. It is actually very scientific. Start with idle, then cruise, then wide open (dyno needed for the last part). It really helps to have a wideband tool with MAP and TPS.