Best bang for the buck?

I agree that sub frame connectors are the single best thing you can do to a forty year old car to make it ride and handle better. That being said, I would ditch the forty year old drum brakes and upgrade to some later model discs. I had nine inch drums on mine and I never knew what good brakes were until I changed to discs.

That project can be done fairly cheaply and it may save your life!