Ok there is no way he was timed at the batsmans end at 160 unless it was a full toss. In fact, it is almost impossible that he (or anyone) was timed at the batsmans end at all.
We know the 1979 tests were at the bowlers end and he was around 90mph. However that was past his prime and he hadn't played cricket for a while so I can believe that at his fastest he was maybe 155-160kph but beyond that is most likely fantasy.
Baseball pitchers are faster (both on average and at top speeds) and none of them ever came close to 180. Afaik the record is around 105mph, which is 168kph.
EDIT: I have no problem believing that Thommo was the fastest ever. But let's be realistic about the speeds.
EDIT2:
We just had this discussion a couple months ago.