Lots of good advice already!
Bigger T-bars would be high on the list. Remember, if it bottoms, spring rate goes to infinity...massive understeer.
Some kind of zero-flex front swaybar links are really a great upgrade -- unreal how much they help 'turn-in'.
Frame connex / torque boxes also rate high.
KYBs, as mentioned, are in the $9.99 'Monro-Matic' league. Bilsteins are excellent, but my personal preference is still the classic Koni adjustables. While no longer sold in the US, you might find 'em down under; my last set came from France.
Be sure any rear swaybar is frame, not axle, hung. If not adjustable, start small -- with a light engine, it is amazing how easy it is to make an A-body into a Corvair / early Porsche!
While more "steering" than "suspension", K-member reinforcements help, or FFI's new bolt-in lower pitman support bearing kit (designed by....;-> ). Also consider Pedders urethane offset upper control arm bushings (also Aussie).
Rick