Attempting to make second deal. Unsure of what to offer.

[Matt Himes]

Hi there first time posting. I am in need of a little guidance from the community.  
currently have a 5plex and 1 sfh free and clear cash flowing 2500$/month. looking at a 6 unit in Bedford pa.
It is fully rented bringing in 40k/yr after 10% vacancy. total bills and taxes are 22k currently. Roof is 8 years old exterior is brick and in great shape. Interior is in need of major work. Walls and floors are 90% but bathrooms, kitchens and carpets will all need replaced. The only reason people are renting there is the severe lack of rental space in the immediate area. I have yet to make an offer but my thinking is, 

Arv=450k

Repairs/updates=120-150k 

So offer should be 170k? Does that seem right? I have cash for at least what I’m willing to pay for it and a decent emergency fund for myself and the rentals and family who are willing to do lending for the Reno if things move faster than I can cash flow. Also I can do a lot of the work with my wife’s help. Any other questions let me know and thank you for taking the time to help out a noob.