Which Harmonic Balancer/Vibration Dampener to Use (350 SB)

[burnin oil]

Just replace it with a quality new balancer of the same size. The larger balancer does a better job of absorbing the vibrations but is not needed on a basically stock setup. To swap it you would need the larger balancer with the correct timing tab for it. If your timing cover has the tab welded on then you would need to swap the timing cover also which involves dropping the oil pan. There is nothing wrong with the small balancer and they are readily available for approximately $75.