Isn't the toughest previous scale 91/100 for a 170? I doubt it'll be tougher than that.
There have been -8=170 a couple of times (most recently in June '07.)
I thought today's LSAT was on the easy side, in the context of the post-2005 exams. LR were normal, games were easy, and RC, while not easy, wasn't as bad as some recent tests (PT53, for example.)
I'll guess a -9 for 170 curve. -8 wouldn't surprise me, -10 would be awesome, and I don't think it will be any more generous than that.
But here's hoping I'm wrong.