Torsion bars the bigger the better???

Dana67Dart said
Assuming the length, metallurgy, and shape are the same, larger diameter only increases the spring rate, (as in stiffer) the ride height will be determined by the adjustment.

For the ride height the indexing on the hex ends also matter, especially with the large bars. You can get into a situation where the range on the adjusters isn’t enough if the indexing isn’t right. I think most of the stock bars are indexed 20*, usually aftermarket stuff over 1.06” or so for A- bodies isn’t offset at all.

autoxcuda said
You can over spring a car.

depends on weight and setup.

I run 1.14”. You need shocks to control stiff springs.

there’s autocross nationally competitive old Mopars running 1.25” T-bars (largest possible). It’s a ~3200 lbs E-body with lightweight components.

You can actually run larger than that!

Some C-body’s had torsion bars with a 1.41” hex. So the B-body NASCARs and some of the T/A and AAR cars used C-body anchors and custom bars. Firm Feel will still make you custom torsion bars, so, if you switched to C-Body anchors you could probably go all the way up to 1.4”. But that would be a wheel rate if like 750 lb/in!!!!

1.24” A-body bars would be a little north of 450 lb/in, which should be more than enough for even pretty serious road race cars.

But I agree, you can overspring for your set up. Tire compound and suspension travel matter.