Everyone one is saying stupid idea but no one is giving you a reason why so here it is:

Chances are pretty good that Google will figure out that the sites are related, especially consider the content is probably mostly identical. Therefore Google will likely pick and choose pages from both sites to use in index while ignoring others that are obviously the same. The thing is, you won’t know, or have any say in which pages G chooses to index.

So what will happen for SEARCHERS is that they will see 1 or the other site when they search. It will depend on what page Google considers most relevant to the searcher.

So imagine this from the searcher POV. Brand new customer, never shopped with you before.

Let’s say they search, find a page from the new site, click and convert.

Now let’s say same customer comes back a week later, searches, finds a page from OLD site, clicks through.

They are confused – it looks right – looks like the same company from last week but this site looks old and dated. Now they’re very confused. Do they trust the second site? Maybe the screwed up and the first site was the wrong site?

That’s the way I see it. It’ll be really confusing for site users ultimately ending in lower conversions.