Passing is actually ~1.5 SD below the mean...(I know, semantics). I believe the STD is around 24.
I think 400 is a legitimate pass, anything under that is risky. But I also do not put as much stock in the predicitive value of these yet (seeing as how I havent gotten my score...if it comes back right on the money, then we'll see).
Again, 400 should put you in the clear, 350 is probably the minimum passing score.