Steering coupler mod

Set screw Is on the splined side and sets into the original notch on the steering box shaft. I was going to notch the other side to allow for the “plunge” like the original style coupler. A drilled hole would work too just no room for plunge.
Ok i see what your saying now. I always have a hard time cutting on that black metal and getting the shape I want. I suppose if enough of the shaft is in past the groove a slot would work. But when I think about it more, it is a fairly critical point to operating the car safely, maybe check into other shaft options?