What torsion bars and leafs on a 74 Duster?

So as I remember, my 74 Charger had a very spongy ride. This 74 Duster squats down a lot when you push down on the front. When you drive it feels like a boat. So in my view the bars are weak and I know that the leafs are bad.

OK, so my question is when I look for torsion bars they list from .810” to 1.14” diameter bars. What would be good bar for normal everyday driving and performance? I don’t need smooth/spongy, I need more of a G machine ride.

As for rear leafs, I see leafs that are heavy duty from 4 to 6 leafs.

One more question, does anybody use air shocks anymore?

Any suggestion would be appreciated.

Thanks

Luis