A header for an agricultural harvester comprising a frame and first and second anteriorly facing, oppositely driven epicyclical cutter bar knife drives connected to the frame. A roller shaft extends between and operatively connects the first and second epicyclical drives. The roller shaft or a drive roller drives rotation of a header infeed conveyor. The anteriorly facing epicyclical knife drives effectively rid themselves of harmful dirt and debris thereby prolonging the service life of the epicyclical knife drives.