Valuation of Section 8 Portfolio

[Christopher Brown]

I'm evaluating a portfolio of 40+ section 8 SFHs in C/D neighborhoods in a tertiary market, all of which are 50+ yrs old.  Occupancy is 100%.  No real comps for a portfolio of this size in the area.  Right now the asking price is about $75k/unit based on a cap of 10% against three years of gross income (supported by P&Ls).  Any input on this valuation?  Other markets seeing valuations for these kind of neighborhoods and units in the same ballpark?  

Thanks for any input...