It was a GMD (Granville, Miller and de Lackner) R-6H, specially designed for the Melbourne race and flown for Jackie Cochran by Wes Smith. They had to withdraw at Budapest with engine trouble.
From this site:
http://www.geocities.com/CapeCanaver...515/index.html
The Granville Brothers Aircraft Inc. liquidated in 1933, so although it was the same workforce that built the R-6H (named QED) officially it couldn't be called a GB as that company didn't exist anymore.