Help in installing steering coupling.

Murray, it’s a 68 dart
The front wheels are straight ahead as I can get them without having any tires or wheels on the hub

Professor, I’ll have to look for that again tomorrow, the mosquitoes ran me out of the carport.
It's not the tires and wheels you need to be concerned with. Here's how you do it. Turn the hubs all the way one direction. Now, put a mark on top of the input shaft on the gear box. You really need 2 people here. Now, one person needs to turn the hubs slowly enough all the way the other way while you count the revolutions the input shaft makes. Power steering? should make "about 3.5 turns lock to lock. Now, divide that in half and turn the input shaft back to the center that many times and install your coupler with the steering wheel straight ahead. I don't know why these guys make things so incredibly difficult, when a 5th grade geometry student explain it better.