There's been some discussion on this in the past. Some feel the 2UZ dampner and 1UZ dampner are the same, some think they are different.
I have an 8 rib dampner that was provided by Richwood, which has a larger OD than the stock 1UZ dampner, and "no spokes" and I believe it's probably for a 2UZ.
This is a good question for Lextreme, as he's one of a few who has been fooling with both engines
The main reason I want the 2uz style balancer is it has no spokes to the hub, just 2 threaded holes, as I need to bolt another pulley to the inside of the balancer, the 2uz will be perfect if it will slide on the 1uz crank
Just FYI here's a pic with the two dampners side by side. The 8 rib one that I received from Richwood (which I think is a 2UZ) is on the left and the stock 1UZ is on the right. Both fit on my 1UZ crank just fine.
Thanks a bunch for the info, and posting the pic, the one on the left ( 2uz) will be perfect, looks like enough meat to do what I need, I'll hunt one done