
a power steering box from a Toyota MX62 Cressida. Using a power steering pump from any Holden red 6 will work.
You just need custom steering column, custom mount welded to the firewall, custom steering shaft, custom power steering hoses, and scallop cut out and welded into the position where the original steering box was. The most expensive part was getting the EH/HR pitman arm modified and resplined to fit the Toyota box.
It works really well, and the standard pump and box are easily obtainable or repairable should the need come.
To do it, you need the custom parts to be made by toolmakers, machinists and hose specialists. We had to go to each one individually to get each component made, and kept no pictures or measurements.
Doing it ourselves it still ends up being a couple thousand dollars and about a weeks labour to work each part out.
About the same final cost as buying an original EH power steering and fitting it, but with reliability and normal modern roadfeel