A header for attachment to an agricultural machine is provided with a frame, a driven moveable cutting device connected to the frame, and a driven movable conveying device connected to the frame. A gearbox is connected to the frame and transmits a drive force onto the cutting device and the conveying device. The gearbox is provided with an input gearbox arranged in a first housing and a main gearbox arranged in a second housing. A separation site is formed between the input gearbox and the main gearbox. The input gearbox is arranged at a back of the header. The input gear box is a rotary speed adapter exchangeable for a gearbox with different gearing ratio.
