Best is a working Quadrajet. Buy one tuned up for a 350, because there's little passages and air bleeds that are sized for the setup.
An Edelbrock 1406 or Holley (I don't know the best model number, someone will chime in) will also work fine.
Whatever carb you get, you need to learn it and tune it, not just throw it on there. Any carb that is well-tuned will work better than any carb that is not.