Changing to manual steering.

Which factory steering boxes work on 65 Valiant? And with mine being auto on the column, can I use the Mancini steering coupler to compensate for the length difference?Shaft and splines the same?
I just ordered parts from Speedway Motors 3/4" X 36 spline universal joint a 24" section of 3/4" solid round stock and a coupler 3/4-3/4. I doing away with the factory steering coupler at the gear box just in case of exhaust clearance issues. This is my way around buying a used steering column and cutting it up. Not for this car...but a 66 Dart GT project car.

Dart Wheelie 9.53 dial.jpg