Thanks to all for suggestions - found the problem. The Offy manifold has a gasket between the lower casting and the carb adapter plate. When I took it apart and cleaned it last winter, some dummy forgot to put the gasket back in - huge air leak.
Also had to go to a -4 secondary diaphragm to close the secondaries. Holly calls for a -2 but that would not allow the secondaries to fully close.
It runs so sweet - 'way smoother than the 2 barrel stock setup. Have yet to crack the 4 barrel open, only doing garage tuning at the moment.
Engine summary:
1979 2.3, bored .040, decked to clean up, .050 milled head, solid lifters, double valve springs (90 pounders), Racer Walsh Stage One cam, Racer adjustable cam pulley, Offenhauser dual plane intake, Holley 6299-1 390 cfm four barrel, Hooker exhaust header, Arp rod bolts and flywheel bolts.