Thanks to All,
Tony, you might be right, but I watched the parts guy pretty closely and we narrowed it down to a damper for a 73 C10 or Suburban 250 which had the same number because the G10 wasn't listed. I have a feeling that light truck 250's are all the same though.
It's an aftermarket damper though, so I wouldn't be surprised if there was a caveat saying a spacer was required between the gear and the balancer that was conveniently missed.
I'm going to pull the balancer till its flush with the end of the snout and see if the wobble goes away. It's currently scrapping the oilpan/frontcover junction and wishful thinking has me believing that maybe the scrape is causing the wobble. If not, I've just learned an expensive lesson.
Thanks again,
