A tractor has hydraulically driven wheels at a cab end and castor wheels at an engine end. It can be driven cab forward in a working mode with a header on the forward end. It is rotated to engine forward in the transport position for more stable higher speed travel. There is provided a float module with adjustable and calibrated springs on the header which allows the header to float relative to the lift system on the tractor. The float force is adjusted by raising and lowering the lift system in dependence on an angle measurement of the lift position. The lift system includes a lift cylinder and tilt cylinder controlled to change cutter angle while maintaining a sight line to the cutter bar for the operator.