It would not be possible to fit a 900 series JD head on a CR with cutting and rewelding the feederhouse opening to make it bigger. The second problem would come with making the autoheader hight work. The 74C head has one rod under the right half flex plates going to the right side potentiometer and a separate rod under the flex seals on the left side going to that sensor. It then uses the signals from both to determine the header hight and lateral tilt at the same time from those 2 sensors. Older NH heads used a dedicated hight switch and a left and right lateral tilt switch much like the JD. A 73C head has the large feeder opening but requires a conversion kit to make the sensors like the 74C. That might be an option since there are some 25' and 30' 73C heads around used, with quite a bit lower price than new.