Trash or Treasure? added pics....

I would agree with ^gts340.
Low end value if the entire underside is cancer riden, the front frame rails, firewall, ect....$1200,1300,1400,1500ish...

If its just both full outer quarters, some lower rocker repair, and the car is numbers matching 72ish 340 block (and doesn't have a later model OD 4 speed in it), it appears to just be missing the driver rear quarter window....and might fetch as high as $4500.

Finding the magic number inbetween depends on what he is asking, what YOU are willing to pay and whatever else....

It looks like a good candidate for a enthusiastic new owner!

Good luck!