My friend wants to sell his F100

I have a buddy who wants to sell his 1974 Ford F100. The truck was given to him about two years ago after his grandfather on his mother's side passed away. He asked me on what its worth. I told him that I wasn't sure but that I would ask around. Its a running and driving supercab truck. He said it had a 360 with an auto trans. Only 40k original miles. His grandfather bought the truck brand new. It was stored inside a block building when a tornado came thru and knocked a couple of blocks off and damged the left side of the roof and left side of the truck. Once he got it he put new tires on it and started driving it. After a couple of months he parked it in a barn with his uncle's tractor. Some strong winds came along and blew the barn off its foundation. He said it busted the windshield. It has a super nice interior. I was just trying to figure out a rough estimate that I could tell him. He wants to sell it if anyone is interested. Next time I'm down that way I'll have to stop by and take a look at it again.