Nobody is flying without sunglasses.  8-)  :P

The Operations Manual came from http://avsimrus.com. You will find plenty of manuals there, including Airbus, Embraer and some of the Boeing planes of course. Not to forget some Russian ones.  :D I think I've mentioned that source in another thread already.
I've downloaded that 707 manual in 2009, so I knew about the plane before it arrived in FSX.  :D By the way, she still is right on top of my favourites, together with my Concorde.

Some are
License: Freeware - Free version, Unlimited Distribution
and others are
License: Freeware - Free version, Do Not Redistribute
or
License: License file included in archive (which could mean anything, one has to look at the files)

I haven't gained full faith in their search feature so far. Means you may have to click through some pages within their library. I'd say it's worth the effort and you may only miss some data in the actual manuals, but the 707 one has a lot of schematics to look at, so I'm cool with it while the performance data came from Avsim.com as a freebie. Combine both and you are set.

Here's the link to some Avsim.com files. http://library.avsim.net/search.php?SearchTerm=matt+zagoren&CatID=root&Go=Search Matt Zagoren has put together a lot of those.
Some more general data can be found right on the Boeing page. But that's more for the airport planning with the noise or safety zones or weight on wheels, turn radius and things. But it also includes the required runway length to TO and landing, so perhaps it's worth a look. I'd say that our sim 707 performs slightly better than the real one.