Another thing I learned as I started getting these things is sometimes you're better to just put a saw in the corner for parts and wait till you find a better one eg that 700 may only need a carb kit to be a runner so rather than steal its muffler mite as well run the 700 and another 7-10 will come along eventually.
I bought a 10-10 and found its rings worn way beyond it so I thought hmm ok rebuild it so stripped it down and started gathering parts for lots of money only to find an amazing 10-10 6 months later and now that old shabby 1 is parts for a heap of my saws. Handle,carby, starter got my 800 running umm aww screws ,bar plates bar ,clutch the list goes on and on of what fits each other so gather them up when you can. Remember a dead old mac is worth piss all to a random Joe blogs but to you there's hundreds in parts