try spraying carb cleaner while its running & see if it smooths out,if it does,then vac leak or the carb,i am betting on a carb problem

1968 Charger COLD A/C Hilborn EFI
512ci 9.7 compression, Stealth heads, 4.10 gear A518 ODtrans 4100lb,10.93 full street car trim
2020 T/A 392 Stock 11.79 @ 114.5