65 Dart magnum dr. Side exhaust journey

I’m thinking since I have the adapter I may just figure out the distance between my current shaft and the top of the adapter. Cut a piece of stock that length, welded it on and then weld the adapter to that. Then the adapter will just slide onto the power steering box. It’s the bulkiness of the Coupler that is my issue. Your thoughts?
The coupler is there for when you get flex between the body and frame allowing it to move up and down even the very slightest.