we have a well ranking site on the domain(e.g. www.test.com) running for 2 years having good PR i.e. 5 and the site having its 400000+ url indexed and then we have a new site on the subdomain(e.g. data.test.com) which is relatively new(6 months) having only around 20k url indexed.
what we are planning to do is move the main site to a new subdomain(from www.test.com to new.test.com) and promote the other site on the subdomain(data.test.com) to main domain(www.test.com).
what would be the effect on ranking, PR once this switch is done? assuming 95% of the URL's are handled properly through 301 redirect.
any help would be highly appreciated.