Rochester Carbs

I have a 1969 Kaiser Jeepster commando with a 225 v-6 Dautless engine and am having problems with the carb, which is a Rochester 2G    #7027089. It started surging at top speeds so I changed out both fuel filters,fuel pump,put a kit in the carb,new fuel tank,check the fuel lines and am still having a problem with it surging at top speeds.  I noticed that when I rebuilt the carb the owner before me left out the check ball at the accelerator pump so I installed the one that came with the kit. Now she won't idle at all. My question is do I opt to replace it with an after market one or keep it factory and replace it with a new  Rochester?