Well not all carby's of that era had the neg G stall problem... Americans were useing an updraft, 3 ventury, pressurized carburetor, on radials well before the war...
Whether the Russians had the same thing or not, I don't know... Another thing to ponder, is that American radial engine tech was much copied around the world at the time...
Some engines were built under license, by Rhone, and BMW, other designs were just plain stolen...
Actually with a pressurized carb, you could mount it any way you want, up, down, or side draft...
RC