An improved self-propelled grain harvester and threshing machine characterized by the sieves, cleaning fan and grain tank being beneath the grain harvester's threshing system which puts the center of gravity in the bottom of the machine and eliminates the need for conveying the grain throughout the machine for cleaning and to the top of the machine for storage. This configuration eliminates several clean grain conveying systems and reduces the length of the reprocess tailings elevator giving the machine a safe low profile and center of gravity when the machine is empty and the center of gravity lowers as the grain tank fills.