I have a buddy who has a 1976 B210 hatch (the one with three windows down the side). He brought it with him from California. He says he used to get close to and sometimes a little over 40MPG out of it.
It has a few bois d'arc tree dents, and some cows licked a large portion of the finish off on one side, because of where he had it parked, but other than that, it is all sorts of cool. I've got soft spot for old Datsuns anyways.