Can the Drupal 6 search function also index block content? I have a site where much of content has been entered into blocks instead of Pages, Articles or Blogs.  The blocks have then been enabled to show up on specific pages, creating the desired effect for the site.

However, as content as been added to these blocks, the search feature of Drupal won't find the pages that have that content on it.

Are there any options to adjust the search engine features for something like this?  Is there a hook that can be used to customize the search results?
No, block content is not searchable by default.
Have you tried the Block Search module? Seems that is what you need.

edit: After reviewing the module, I now see that the search functionality inside block content is done for only administrators, so that module probably doesn't help.