GM steering box

What steering gear box will interchange with the 71-73 mustang with as little modification as possible. I would like to improve the steering response but don't want to go the rack&pinion route if I can avoid it.

If it's a GM type unit, what about the quick ratio cameros and corvettes? Are they bolt it swaps - or pretty close to it?
 
Do you know of anyone familiar with this swap?

I installed 620 coils with the 1" drop and just recently went from the standard 195/75-14s to 225/60-15s on Magnum 500s. I drives 500% better than before but I know there are still many improvements that can be made. I'm replacing the drums with power disks tomorrow. Subframe connectors and bigger swaybars are going on in the next month or so.