Leveraging interest on a popular blog post, with a new, expanded page on the subject...

[bizzer]

On a wordpress site, I have one blog post that performs extremely well for Adsense revenue.  But the post is getting older and older, and requires me to place some updates into the article from time to time. It's a blog post, but really feels like more of a reference types page (it's about stocks in a particular industry).

Now that I see so many people landing on this page through search (#1 for the term), I'm thinking I really should really develop this information further, and make a reference page out of this information and keep it updated, with a link to it from the nav menu.

However, I don't know if it will be bad to have both the reference page and the old post page trying to rank for the same keyword term or not? (They won't be duplicate content, the new page will just the same topic rewritten and expanded). Is that something I can get penalized for?

I'm getting very good income off of this existing blog post and don't want to mess it up, but I also know that only keeping this info on a post that's getting older and older is not a good long term plan, and I need to pounce on the interest in the subject matter.

So, I see these options:

1. Create the new expanded page, and let Google sort it in the SERPs.

2. Create the new page and redirect the old blog post to the new page.  That just doesn't seem right to remove access to my old blog post, though.

Which of these is the right thing to do, or is there some way I'm not thinking of?

[EGOL]

When I have a page that is getting a lot of attention I write pages on related topics and link to them from the popular page.   Do your best to target different keywords but if that is not natural you might be rewarded with #1 and #2 listing for that keyword.