WWW vs NON WWW.will switching it affect my current SEO status?

[Webfanatic]

Hello all

I have a very old website (almost 15 years) that has never indicated its preferred domain in Google Webmaster tools.

I want to switch it to all WWW. So, the way to go about this is setting that within GWT and then setting a 301 redirect in my .htaccess file. The site contains a large Vbulletin forums and some static pages. Right now the site is ranking quite well within Google for our keywords, however, it has been slipping a little over the past year or so i want to keep up with the times and make some positive SEO changes.

My question is....if i do set up my preferred domain with the 301....will this have any NEGATIVE impact on my current ranks? There are quite a few forum pages so I am scared that Google may see this sudden change (basically I'm eliminating hundreds or thousands of non-www pages) as some sort of negative event and penalize me for this.

What are your thoughts on this? Anyone have any experience?

Thanks in advance.

[netmeg]

When I'm faced with one of these, I take a look at which version is ranking best and/or bringing the most traffic, and that's the one I keep.

That said - I've switched from one to the other and recovered back to normal traffic within a week or two (several times) but those were sites that were already doing pretty well.