Torsion bar question

Yes. My 1965 Dart w/ 273 and no factory AC (rare option then) had 0.85"D Tbars. I got a pair of thicker bars (0.87" I recall) at a local swap meet for $15 (great deal, seller had several sets on the table). I put the 0.85" bars in my 1964 slant (no factory AC) when I rebuilt both suspensions. You can also buy new thicker T-bars. The best-priced ones are one size (1.00"D recall, maybe $200/set), which are much stiffer and eliminate that "boat-feel" to make it handle like a modern car. Most who have done so don't find it overly-stiff. They fit all A-bodies (until Aspen/Volare F-body ~1978).

Be glad you don't have a C-body. New T-bars cost ~$350/set if you can even find them and used ones are pricey too. Mine were sagged in my 1965 Newport. I lucked into a 1965 convertible at PicNPull and grabbed those since thicker. Now my Newport rides at the correct height with the adjustment bolts less than halfway in. Convertibles are heavier, so likely have thicker T-bars (not in chart) or maybe because that vert had a bigger RB engine (forget). My Dart likely felt like a big boat as-found since it had a heavy after-market Tecumseh compressor (like York but cast-iron), probably even heavier than the Chrysler RV-2 beast. Both A's have a small Sanden compressor now.