This is just a brief note to let you know about:
Buick 455 harmonic balancers are no longer available from GM so the existing ones need to be rebuilt after 25 plus years of service. The elastomeric ring that separates the inner and outer metal ring usually becomes brittle and cracks. Eventually the outer ring will rotate and possibly come off the inner ring which can lead to engine damage! For $112 for the 455 and $87 for the 350, Damper Dudes will rebuild your damper to like new specs. Check their site for more info!