I don't believe the height between RB and B brackets are much different. The difference would be where the cable and kick down attach due to the intake being wider because of the raised deck. The rod down to the trans is also taller for the 440 due to the raised deck. Those do look like 440 pieces you have but the rod is hard to tell as it disappears behind the engine.

I would start with getting the thick gasket used on AVS carbs, that will raise the carb close to 1/2".

Does the throttle cable and linkage lever appear to connect to the carb straight looking down on them?