bowties,
I am not real up on this but I thought there had been mention of a Toyota 4WD steering box working on these old trucks. I think the thrust of this swap was the fact that the box mounted quite similar on the frame and the Pitman arm was in the same plane as the AD trucks.
IF..this is correct, the tech part would be grafting the AD column to the Toyota box. The pump would have to be mounted to the engine too.
Maybe this isn't "off the shelf" enough for your plan though..more info will probably be along soon.
Stuart
