I don't like using the short box couplers because the shank is different on the coupler end. I have found they have less side to side swing than the standard medium shank couplers. I need 072 ability and I always have issues with those 806's, especially on engines in multiple unit consists.
Here's the difference on the nose of the A units. I have 2R pilots ordered, so that big hole will be disappearing soon. Once the 2R pilot goes on, I'll cut the trip pin off, and add an air hose to the pilot.
Here's the gap with Kadees, 740's. Still quite large.
Notice the A unit coupler sticks out quite a bit further than the B unit.
The Kadee bracket is mounted further back on the B unit because there is more room. The powered truck of the A unit really limits the space for the Kadee mounting bracket, and I had to modify it just to get it to line up with the mounting holes in the frame.
You can see the gear box on the rear of the A unit, and that's what is limiting the coupler mounting space. I'm going to modify the coupler box, drill a new hole in the bracket to mount the coupler further back. I might only be able to use 1 screw to secure the coupler, but it will be sufficient.