Splitting our main website in Two... What is the fastest way for the new sites to become a brand in Googles eyes.

[Hyrule]

In a couple weeks our main website (which generates all of the revenue) will be split into two because of a long term branding / identity crisis. So my question is, how can i make sure (besides obvious 301 redirects) that these 2 new fresh urls become a brand as quick as possible in googles eyes?

So far i am thinking of things like: press releases, blog posts with brand mentions. I am not ignorant and expect this to happen overnight, but we need a strong foundation to build on, which is why i am asking

Anyone got a list / case study / advise so I can really blow it up on launch week?

Thanks

[HandsomeWeb]

A competitor to one of my clients split into to companies (and two websites).  They had invested a lot of money promoting their original domain, and there were loads of good links in.  They 301 redirected all pages in their original site to their original home page.  That page is still up but has an explanation of the split and one link to each of the two new companies.

I believe their attempt was to take all the "linkjuice" and split it evenly between the two companies.  Then it is regular SEO on the new sites.

It was probably important than the old name stays up, and the new companies have new names.