Blogspot to self hosted wordpress without losing any ranking

My friend ask me to migrate his blogspot to selfhosted wordpress with brand new domain name. His old blog which is blogspot contain lots of decent stuff and ranking lot of term. So is there any way to migrate carefully from blogspot to self hosted wordpress without losing any ranking in Google?

I kinda new on this, maybe some of you (forumers here) can give a tips.. yes i knew i can Google it.. but maybe a few handful tips could help me along the process.. i am just afraid i am not doing a right thing.

Thank You

Just try with some migrate plugins, backup all the data before and test to see if all is OK.
Also try to crate same link structure or do permanent redirects, other should be fine.

Any update on this? I happened across about 40 aged high PA Blogger accounts

By the way, can backup database from blog like blogger or blogspot then tranfer to other blog ? This is not website to download database.

This is very interesting topic, but i never used it, but i want to know about it, Thanks.