Hi,

I have just started using a new cms system which will replace my old static html site. My problem is that the site ranks very well for some competitive phrases and i am very worried that my site will dissapear once the cms goes live.

I have thought about using 301 redirect from old page names to new name but i think this will be a problem as it will mean google may still keep these pages indexed but their importance would dimish as my index page no longer links to them and i may get some sort of penalty for having duplicate content on the site.

Im half geared up to throw caution to the wind and just completely replace everything but i have never made a change this drastic on a high traffic site. Please help.

THERE IS NO PENALTY FOR DUPLICATE CONTENT

It is a filter, all that happens is the pages that are less important to the algo do not get shown for that query.

I have thought about using 301 redirect from old page names to new name but i think this will be a problem as it will mean google may still keep these pages indexed but their importance would dimish as my index page no longer links to them and i may get some sort of penalty for having duplicate content on the site.

Not true. When you redirect from oldpage to newpage then the old page PR and traffic are redirected to the new one but the old page is slowly removed from the cache. If you dont redirect then Google will have both of them in the index and can cause you problems for duplicate content but when you have redirect and Google finds the old it will be redirected to the new one.