difference between a 65 dart steering box and 67 or later

How...how do you know these things Roy?? You amaze me sometimes!!
Some of it is knowledge from the internet. The rest is hands on. I searched for a long time to find where I could buy those funky looking bearings on the front and the rear of the worm gear sector. I buy these boxes up when I can and rebuild them from time to time. I'll have about 10-20 boxes on hand at any time.