An agricultural harvester (10) includes a chassis (12) and a threshing and separating system (24) carried by the chassis (12) that is configured for threshing and separating grain from gathered crop material. The threshing and separating system (24) includes: a rotor (40) defining a longitudinal axis a concave (42) at least partially surrounding the rotor (40) a transition cone (92) defining an infeed to the rotor (40) and a transition surface (94) connecting the transition cone (92) to the concave (42) and having a conical portion (96) defined about the longitudinal axis and a blended portion (98) connected to the conical portion (96). The blended portion (98) defines a first end (102) connected to the conical portion (96) and a second end (104) distanced from the first end (102) in a lateral direction. The blended portion (98) defines a substantially conical shape about the longitudinal axis at the first end (102) and approaches a substantially cylindrical shape about the longitudinal axis toward the second end (104).
