Harms Rebuilt '71 Thermoquad - Wondering Idle, Stalls when Put in Gear

Ok. At my witts end. I have a Harms rebuilt (2018) 1971 Thermoturd that was never run. Bone stock 1971 340 except has electronic ignition. Installed carb with new base gaskets (twice) and I'm only getting about 9-10 inHg vacuum. All external manifold and carb vacuum ports have been plugged. Timing currently set at 16 degrees BTC with total 35 degrees all in by 3000rpm. Good throttle response on road but stalls or nearly stalls when I stop the car at a light. Carb responds to air-bleed adjustments (stalls when turned all the way in) and I have them out about 4 turns for best vacuum and rpms. Idle wonders from 880 to 980rpms. I've tried various timing combos and adjustments, air bleed adjustments, etc. without success. Car stalls or runs about 350rpms when I put it in gear. I sprayed WD-40 all over the intake runners but no help. Thing is, I had a new Edelbrock 750 cfm with 1inch square bore to Thermoquad bore adapter and old base gaskets and I didn't have this problem immediately before installing the rebuilt thermoturd. Motor doesn't run hot and plugs look good. The rpms pick up slightly when I cover the air horn with my hand. Replaced coil - no help. Plugs, cap, wires, rotor all replaced within the last 500 miles. Anyone have any ideas what to try next?