Well, there are some documents at Avsim that I don't remember the name of. Those documents do have some basic flight planning information. However, if you're like me and want as complete data as possible, then I would recommend you to take a look at this: http://www.esscoaircraft.com/p-8169-pan-am-pan-am-707-1976-operating-training-ma....

I bought it myself and I'm very pleased with it as it includes all EPR values that you could possibly need, fuel planning tables and etc... well EVERYTHING you need actually. (even tables for 2 & 3 engine operations)

It is available as either a printed version or as a download.

If there is someone who is able to fix the EPR issue or wants to fine-tune the fuel flow, contact me and I'll provide whatever data I can.

CoolIP is correct. The only stuff I have found on the net so far (that you don't have to pay for) is Matt Zogren's stuff which is at AVSIM. I have a copy of it and supplemented this with some material on the 707 from the Boeing website. I just worry about fuel flow and not so much about EPR as I have no idea what is precisely the engine version Capt Sim used as a base model for the engine algorithims. There are various engines with different cowl configurations so one size does not generally fit all if your after exact precision but they are all in the end about the same and I can live with the differences. Just keep the engine needles out the red zones and your right and the rest depends on the day you fly and what the outside air temps are where your flying or intending to fly and then go for the expected fuel burn per engine from the Zogren tables (which came from Boeing anyway).

We can always hope. The last news from Michael2 was that he's a young father now and that all tuning and tweaking is based on the 'as time permits' basis. So that's a thing to keep in mind. However, that's from some months ago.

On the actual problem with e. g. EPR readings, he had some tweaked gauge on the 727. So it got replaced and then delivered better values together with the other teaks of his. Now the 707 comes with 3D gauges and a change isn't that easy to do. I think he actually tried and received very funny pointers on the gauge itself.
In my humble eyes, the FDE tweak on the 727 helped a lot, while I think that the default 707 already gives a nice feel. So there may not be an urgent need.

However, I'm glad to read about some fans of his work. That's the best appreciation one can get and you folks can count me in. 

Thanks for the kind words above.

I did start on a flight model mod for the 707.  However, I ran into a problem with the way the gauges are coded.  It was a while ago, but I seem to remember that the gauges had needles that were 3d objects that I couldn't control or get rid of.  I ended up having to add a second needle to the EPR  gauges and painting it with stripes so I would know which one to read.  And I could only get all four gauges to show readings for a single engine.  The end result would always be compromised and it just wasn't worth the time (and money for manuals) that I was spending on it.  

So now, after a period of time off from flight simming,  I am spending what time I have on creating a DC-8 from scratch.  It's a big project and I'm not entirely sure it will ever see the light of day, but I am afraid my days of modding other aircraft are all over.