rear sway bar recommendations

In my experience gradually building up my Duster for handling at the track, A-bodies are very understeer-prone and need a rear sway bar especially if bigger torsion bars and a front sway bar are installed. I think with old-school slippery skinny tires they might tend to oversteer with a rear sway bar but even with a Hellwig 7/8" adjustable rear bar and Hotchkiss leaf springs it's not easy to get the rear end to swing out on my '70 Duster. Granted I am running wide modern low-profile performance tires on 18" wheels but even with my old Firestone Firehawks on 15" Rallyes it still understeered way more than oversteered.

For street driving if you aren't pushing it to the limit a rear bar will still make the car feel more nimble and "pivot" around corners more than "push through" like they do without it.