Fluidampr Harmonic Balancer: Remove dangerous torsional vibrations and gain power at the same time. Engine internals are subject to high stresses. When power increases are added this stress is multiplied. Bring your engine back to a safer level. Not only will you feel the difference you will gain power at the same time.
Yeah....I have been doing a bunch of reading on this also. Back in "the day" I had one of these on my old '66 Galaxy. That old cammed 390 seemed to like it. I just can't bring myself to spend $400 on something I can actually "see" every day!!