Is this 76 280Z worth getting?

  The Impala takes up nearly the whole garage.

In arizona thats a big minus.  I used to wash my car inside the garage because it was too damn hot out in  the az sun. Having to park good cars out in that sun

really ruins the paint/upholstery fast. 

If it were me, i'de sell the impala and get cash. Point out all the work it needs and then offer this guy 5000-6000 and use the leftover  to fix up the car.