Didn't bother to read a thing did we?

In a Chrysler longitudinal torsion bar suspension the spring rate and the wheel rate are IDENTICAL.

Spring rate is spring rate regardless of diameter. The reason the A body bars are stiffer for a given diameter, which no one asked about, is that they are shorter. So if you want an A body T bar to match the spring rate of a B body T bar the diameter will be smaller, but the spring rate and the wheel rates will be IDENTICAL.

They say there are no such thing as a stupid question.
They say there is always the exception that proves the rule.
Don't be the exception.