Problems?

Right now I'm running 3.91's with a Fairbanks 3000 converter. Against the brake it will stall about 2700 rpm. I'm getting tired of the higher rpms of the 3.91's. Since I put air-conditioning on it a couple of years ago I'm trying to drive it to more shows and cruises. I was thinking about swapping the entire rear housing out with the factory housing. It has the original 2.94's in it. I was wondering if I would have any problems with the size of the converter with these higher gears. Anyone with a similar experience with doing this?