The two year design-development program for the sonic carburetor is reviewed. Use of the sonic nozzle as an air flow meter, and the design criteria to achieve low unchoke points is discussed. The relation between sonic flow and improved fuel atomization and A/F ratio distribution to the engine is also discussed. Unchoke data and A/F distribution data are presented, and the tradeoffs between low unchoke points and good A/F distribution are explained. Conclusions are drawn relative to the overall benefits of the sonic carburetor.