Take a look on this thread on Speedtalk. Wolfplace (Mike Lewis) is a very credible engine builder. I don't always agree with him on parts selction for power, but never on how to put a motor together.

See the pics of his a few posts down on;

http://www.speedtalk.com/forum/viewtopic.php?p=17531

Here's one:
Want this to happen in your boat ?

http://wsm.ezsitedesigner.com/share/...Damper_002.jpg

It tells the story; in and out of the throttle, the outer ring is moving so much it won't stay together.

I forgot BHJ, I use their fixtures in machining.

Yikes. Thats scary.

I see the powerbond balancer MER mentioned is avail at a good price. Seems like a quick internet search yielded some good reviews on them. I believe my local "enginepro" distributor, sells these balancers under their enginepro label.

Also, consider this.........
When a dampener fails in a car, the pavement gets a scuff in it from the flying debris.
When a dampener fails in a bilge, the hull may get a nice "window" in it from the flying debris.

I don't want a gaping hole in the bottom or side of my hull!

This is one my shops been using with zero issues so far....

http://www.summitracing.com/parts/tf...make/chevrolet

true story,back in the drag boat days one of the guys was using a cheap balancer.when it let loose it put a hole in the bottom of the boat,2 minutes later the boat went under.