borgeson steering coupler

Does Borgeson steering boxes and factory steering box have same size input shaft. Bought Borgeson coupler 036425 and having hard time putting on shaft. Had my factory box rebuilt by redhead 63 dart.
Our box / coupler does not have the same spline as factory, Factory power boxes are a 5/8"-36 spline, factory manual boxes are a 3/4"-36 spline and our power steering boxes part #'s 800126 & 800127 have an 11/16"-36 spline. The 036425 coupler will not fit the stock boxes.