I would agree with most that he's expecting too much.
I picked up an '81 280 automatic a little over a year ago for $3500 - tired interior, minor left fender damage, tired paint, a/c questionable. I probably paid too much, but I knew goiing into it how much I would spend to get it back to "very good driver" condition ( none of mine will ever be "show" - you don't drive a "show" quality car).
My secondary motive was to be able to use it as a guinea pig in tackling an interior refurb project. I'll learn on the 280 and then be experienced when I redo my 500.
I didn't see anybody say it so I will - take your time, study here and know what you're looking at and what you'll need to put in it after you buy so you know your total 1st year cost.
They really are out there so be patient.
Best regards,
Kevin
P.S. - oursl(dot)com lists a lot of 107 cars. You can get a feel for condition and high/low range $ there
P.P.S. - The M110 is a great engine (3 of mine are M110 powered)...