Hi Domino, I'm afraid that I will have to really mess things up here. I am running a NEW Zenith Fuel Systems #14991 carb on my '29 roadster driver and have been for 3 years now. Its is slightly larger than the 12932 you have above, and is atmospherically balanced, meaning, among other things, that you can run a modern air cleaner on it without losing gas milage or affecting gas/air mixture, etc. The choke and throttle linkages fall into place, and will require about an hour or two to modify to use original choke rod and throttle connections. Once done, you will be able to switch between your new Zenith and original equipment in five minutes if you so desire.
The best gas milage I was able to get with the tuned up original equipment was 18.5 mpg. The milage I get with the new Zenith is 18.5 mpg. The power curve over the entire engine range is much smoother than the original, and I can't say enough about how evenly the engine runs. One drawback is that you do not get that nice little choke rod hookup I see in the picture of your 13922 - you would have to make your own, as I did on mine.
If you are planning on doing this, I recommend that you look into the model 14991.
Happy Motoring!