Abstract: A crop harvester header or platform includes a rotary cutterbar for cutting and directing crop to a crop conditioner having a length shorter than that of the cutterbar and being disposed centrally behind the cutterbar. The header is equipped with a crop converging structure including right- and left-hand drums or cages respectively mounted to the tops of right- and left-hand cutter discs respectively at opposite ends of the cutterbar, and further including right- and left-hand crop guiding or directing structures respectively disposed for guiding crop from forward locations of the drums or cages over the cutter discs respectively adjacent the end cutter discs and toward the crop conditioner.