How to get rid of understeer in a 1970 340

I'm going for new Bilstien shocks and going to have the torsion bars and springs looked at , they are over 7 years old , might be time for a change . Wil see how that helps , then rear sway bar .
Thanks

Existing springs will be fine. You don't drive it daily or anything. If they are not sagging the only real way to check them is to remove them and put them in a Spring Rating device/tool.