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thanks for the help (and good analogy). looks like it's time to start testing a few  combined pages

the only major difference between the products is the kind of capsule we use to keep them in. other than that, the page content is exactly the same. the only differences i've seen are the urls, the page title, and 1 link pointing to the alternate form of the product (gel caps product page has a link to veg caps, and vise versa)
we aren't using dynamic url variables, they appear as http://company.com/bcaa-gelatin-capsules

it's starting to sound better in the long run if we just merged them to be on the same page...

In cases where it is possible, it is best to get the links that are pointing towards the old pages changed so they are pointing towards the new ones in addition to setting up a 301 redirect. 100% of the link juice isn't passed through a 301.

In a site with a mountain of external links, prioritize those with higher PR, Page Authority, or MozRank. Don't spend all your time on it, though!

In cases where it is possible, it is best to get the links that are pointing towards the old pages changed so they are pointing towards the new ones in addition to setting up a 301 redirect. 100% of the link juice isn't passed through a 301.

In a site with a mountain of external links, prioritize those with higher PR, Page Authority, or MozRank. Don't spend all your time on it, though!