Which Dampener are you guys using?
I've been using the Pioneer SFI 872037 on my race 360's for years without any problems. Summit has them for a reasonable price. (Disregard the pic on the Summit site because they used a generic photo for that part.)
http://www.summitracing.com/parts/PIO-872037/?rtype=10
If your engine is definitely internally balanced and the current balancer/damper does not have any counterweight on it, you can simply swap them out.