Maybe you already looked at the 1929-1954 parts book.
This illustration seems to call it simply a hangar.
http://chevy.tocmp.com/1929_54chevyparts/07/434.HTM If you go to part # 7.112 from the illustration for example, it is described as "Hanger, rear spring front". I'm not sure which hanger you have pictured.
Hope you find your replacement part.
