Appreciate the 318 for what it was designed for: A reliable engine that lasts and lasts.
Of COURSE it lasts a long time. They came with a cam with .373 lift. The heads had ports small enough that a grape couldn't get through. They ran out of power at 4500 rpms. These engines didn't get blown up at street races.
Now....
Take a 318 and fit it with a bigger cam, decent heads and some headers and you'll really have something.