Vacuum on 1968 GTS 340 4 spd.

I bought the car with a 110K on it. The owner said it was bone stock other than a valve job. Always ran good but was getting a little tired. You could push down on the valve spring with the palm of your hand! Now Only 8 in vacuum . Car wont stay running unless partial choked until it is completely warmed up. Original carb worked fine before rebuild. Now has a used 600 Eddy I bought and rebuilt . Then I rebuilt and tried the original carb and had the same results so I put the Eddy back on.Car does idle smooth no mis-fire but stumbles when trying to open secondary s. Timing now initial 12 total 35