My Hotrod coupe uses a stainless steel IFS with a Commodore (Australian GM) rack and pinion steering setup.
I need to connect the early 80's Mazda steering column to the rack and during my trip to the USA York Nationals in June 2001, I managed to pick up 2 Flaming River universal joints.
The column uses a 5/8" x 36 splined end and the rack spline I have not checked as I have the matching short shaft from the VK Commodore which I am going to use.
Updated Jan 2005
The rack shaft, was fitted with a rubber absorption joint which I removed to discover a 5/8" x 36 splined shaft under it.
I'm running two shafts with a bearing on the lower shaft to support it.
Unfortunately, when I set it all up, there was virtually no clearance to the headers. In Australia, we are required to have a minimum of 10mm clearance to any engine part, so I had to rethink.
Replacement headers were considered but I could not find anything suitable, so the solution was to put a bend in the headers and this was done using several pieces of mandrel bent pipe, inserted into the front pipe.
At the bottom of the steering shaft, an alloy bush was made to 'pretty' up the end of the column and also to support the inner shaft by fitting an internal bearing.
A piece of 3/4" (19mm) steel rod has had the ends machined in a "double D" style. All this means is that 0.1" has been machined from both sides where it fits into the uni joints. This was done on a mill/drill but could probably be hand filed, with care. Both ends must be machined with the flats on the same plane, to get the correct alignment of the 2 joints.