having been down this road before putting a hirise dual plane and vac secondary 600 on a previous stock 2bbl with 2.76 gear.
It killed the off idle and bottom end.

assuming the carb is ok..my cure was alot of time experimenting on initial timing the idle mixture and timing curve. getting a clean idle with alot of initial and lighter spring for quicker advance was the fix but you have to deal with pump gas and pinging issues also if your to agressive.

need to limit total advance also since alot of initial and the lite springs will put total to high.

more gear would help if you are running "hiway" gears now.