If I have a PR4 site (site 1) and buy a PR6 site (site 2). Then did a 301 link from the PR6 site (site 2) to the PR 4 site (site 1). What would happen to the PR of the PR4 site (Site 1)? Does Google get upset by this? Any extra advice is welcome. Thanks
From my experience although I am not 100% sure it seems like it passes a little bit. I think it just depends on the links you have. Sorry I dont have a more fine detailed answer
If you will redirect your PR6 site to PR4 website correctly, then you will surely get benefits of all backlinks of your PR6 website. As Page rank largely depends upon the number of backlinks, there are chances that your site wih PR4 will get high PR in next PR update. One thing I like to mention here is that this all will take considerable time, once you 301 redirect your one website to another.
If it is a dropped domain the pr will run out. If a domain has pr6 from say..? raising lamas then you get and redirect it to say.. selling viagra the raising lama domain will turn to pr0.