Just going to add my 2 Cents here. I had the factory balancer on my low deck 470 spin. I picked up a used damper (TCI Rattler) from this site for pretty cheap a few years ago, don't remember how much. I like it for a few reasons.
It is black and easy to rear. It is marked all the way around, including every 90°. It's design will not allow it to spin, ever.
There is a used ATI on EBAY now, but it has a chevy pattern hub. I would shop around for a good used one.