Turning radius can be a bunch of different things. The Lares boxes for GM cars are all based on the A body steering box which have no internal stops in them. Any turning radius reduction you see from an a-body style stop would be caused by wider tires hitting the frame, a steering system that wasn't rebuilt on-center etc.
This is the gear I have.
https://catalog.larescorp.com/part/10972/ You also need a 13/16"-36 spline rag joint to adapt it.
The gear is labeled as a 10:1 ratio but I kind of doubt it's that fast, it's probably actually 12.5 Steering effort will increase quite a bit over the factory box with the .210 torsion bar.