Searching for variable/quick ratio steering box for '72 K20

[RaptorSentry]

I have seen a lot of threads about variable/quick ratio steering box for C series trucks, but have not seen anything for K series trucks.

Anybody know where I can find a variable/quick ratio steering box for a '72 K20? Will also most likely doing a hydroboost conversion for the brakes, at a later date, if that makes an difference.

If there are none, why is that? Is there a clearance issue to make a variable/quick ratio steering box for the 4WDs? Or is there not a demand for it?