[OG68]

The Jeep boxes have a .195 T bar and are much firmer (20-26 lbs) than the stock A body box (15-21 lbs) but not as firm as the .204 bar (24-30 lbs) found on the late 80s Monte SS, Hurst Olds, Buick GN which as you said, have a different turning radius. I can't explain why the Jeep box is firmer with the same T bar but when I changed my stock El Camino box to the Jeep box the difference in firmness was evident.

Jim Shea Steering Papers are a good read on this subject.

http://jimshea.corvettefaq.com/?cat=4

Edit;
As I read through the different models in Jim's papers I noticed that the early Camaros had the same effort as the early A bodies, 15-21 lbs, but are listed with a .175 T bar. Makes me wonder if the .195 A body T bar size is a misprint.