This website says that currently you'd need five A*-Cs.
This document states that under the reforms, a 4 is equivalent to a low C.
So I think it would be reasonable to assume that the new requirements will be around five 9-4s. If you want you can look on the UCAS course search to see the entry requirements at specific universities; some of them are beginning to list their requirements in terms of the new system. Google is your friend