BigDave - 12:39 am on Nov 22, 2006 (gmt 0)

You *will* get a drop in traffic.

The absolute best case is that Google takes your current results out of the index and the new pages go into the index at the same time. Google credits your 301s within a month, and takes another month to recalculate everything else.

Since the new domain is not the old domain, it will not get any benefit of any age related factors. You also have a new domain that is suddenly appearing with 50K pages.

If you are lucky, Google will recognize that it simply a new domain name on an old domain. It isn't the sort of luck that I would want to bet a business on.