I daily drive my '73 Dart with 1" torsion bars from JustSuspension, Hellwig swaybar on the front and adjustable shocks all around (Hotchkis front/ QA1 rear).
7 leafsprings per side.

Looking at my own torsion bar 'step-up' from .89" to 1", I think 1.06" or 1.10" would have worked for me as well.
For all racing and competition, I would follow the folks here saying go with a more serious torsion bar.