Only the very last of the 535's had the option of what was then considered a "quick-tach" system. Long tapered castings that the feeder house which was permanently fixed to the head would slide into. The 7300 had a true quick tach like other makers where the feeder house was on the combine. There are two main styles of 700 series corn heads for the 7300, the early style with the slip clutches internal to the row unit gearbox, and the later MUCH better style with external jaw type clutches. Corn heads for the 7300 were numbered 70XY, where "X" is the number of rows, and "Y" is the row width (ie 703N is a three row narrow). As I recall the narrow were adjustable from 28 to 32 , the wide from 36 to 42.