How should my duster handle

A few comments.

1...These old girls can handle pretty well with nothing more than replacing worn parts AKA bushings, ball joints, etc, getting wheel bearings up to snuff, and getting them aligned / per type of tires and aligned RIGHT

Since most of us don't know the history of our cars, I would replace EVERYTHING that moves such as bushings, ball joints, tie rods, etc

2...Tires make a tremendous difference, not just size and pressure, but sometimes one brand to another will make a huge difference

3...Don't forget rear alignment and spring bushings

4...Good shocks. Do not need to be anything tremendous, just good heavy duty shocks

5....You need a front anti sway bar even if nothing more than factor type

6....If possible get heavier T bars, V8/ at least.

7....You don't need a lot of money sometimes. My 67 had stock rear leafs, marginal. I took the spring packs apart, and the packs of a junker, and combined both using the longest of each. Put in same total amount +1 leaf and it just happened to be "right."