If you want them to actually be fun to drive (and less dangerous, therefore), you get "rake" with the springs
and a little bit of torsion bar adjustment; the rest you get with tire diameter differential.
I like a little bit of rake over stock; mine is all tire with a touch of bar:
These cars actually were known to some of the better handling cars of the day and they do drive pretty well
IF you don't go all crazy with aftermarket stuff. Mine, even with the factory springs and such, can be tossed
into a corner pretty quickly (just watch out for the tail to step out on you - these things will actually oversteer
near the limit without a rear sway bar on them!).
Rides beautifully, too - I always loved torsion bar ride over any of the GM stuff I owned in younger years.
No wallowing when you hit a bump or dip - you get the original impact, then solid straight again.
They sat pretty much dead level when new, so you could tell when the rear springs were worn out on them
from the droopy tail look:
The factory engineers did that primarily to make the cars handle as neutral as possible
(or even with a bit of limit understeer) so that the average driver didn't as easily get in trouble.
Of course, this excludes factory drag packages and such, but for the mass produced vehicles,
a little understeer was thought to be easier for the average driver in emergency maneuvers.
That's still the case today, by the way - short of specifically built ultra high performance models,
factory engineers dial in a little of at the limit understeer in pretty much everything.