Edelbrock Performer vs Edelbrock RPM Airgap

Every time I have used the Eddy Performer 4 barrels they have had a sort of flat spot off idle, like the engine just kind of falls on its face for a split second. Get the timing dialed in first. The only tuning I have had to do with the Edelbrock carbs is to switch the pivot point of the accelerator pump (move the linkage to the inside hole) then fine tune with springs and metering rods. The O2 sensor and gauge might make it easier to tune, but probably isn't necessary. In my opinion, the carb / manifold setup you have should work just fine. With the setup you have, i would be willing to bet the stock jets that were in that carb would do you just fine. As Crackedback stated, initial timing at the distributor will make a big difference.