A Google Webmaster Help thread has someone complaining that his site's rankings dropped and the one thing he noticed was that his home page and 56 other pages are indexed in Google with the https version.
To which John Mueller of Google responded:
Before you get too focused on technical issues, I'd just like to add that going from https to http, or the other way around, generally won't noticeably change your pages' ranking.
So he is implying that there may be something else here to blame for his ranking drop and not the HTTPS issue he is citing.
But is it true that switching from HTTPS to HTTP or the other way around "generally won't noticeably change your pages' ranking?"
Six months ago or so, we covered that making the switch is doable but you need to do it right. Matt Cutts also posted a video on the topic in 2011, of course, things change quickly in search, so I am not sure if he would be as reserved if he made the video today:
Assuming the 301s are set up correctly - I'd say there may be a small down side for a short period of time, in switching from HTTP to HTTPS. Would I make the change here? Nope, not yet at least. I would in a second if Google passed me query data. ;-)