The Holley 94, 2100 and 2110 use 2 idle tubes (#44). You can get a rough idle if these tubes are plugged. These have very small orifices and need to be clear. Ethanol will leave residue behind so normal cleaning may not do the job. Very thin wire can be used to push the residue out, just don’t damage the hole making them larger.
The tubes simply unscrew but if stuck, then apply a bit of heat to the outside of the venturi. That will usually kick it loose.
Make sure the gaskets #54 are in place and not split, or damaged.
Idle Mixture Adjustment
After the carburetor is installed on the vehicle. Warm the engine to normal operation temperature. Make sure the idle screw is resting on the lowest part of the fast idle cam. Set the idle to the manufactures specifications. Turn the idle mixture screw out (counter clockwise) as far as possible without killing the engine. Adjust each idle screw by turning in 1/4 of a turn at a time, then wait for a second while the engine catches up. Do this until you get the best idle rpm. Both screws should be close to the same number of turns out. This indicates a good idle mixture balance between the two barrels. Keep in mind that you want to set the idle mixture while the throttle is closed as far a possible so that the fuel is being drawn from the idle circuit.