tricky one, pricing up a restoration project... it purely depends on the right person seeing it at the right time.
if everything panned out right i'd think maybe £3000 or so would be a realistic top whack, possibly more if its an SS or 2 door. might have to wait for the right buyer though.
is it 2 or 4 door? was the 5.2 the original engine, if so is it still available? (numbers matching cars always fetch far more money) any chance of any pics?