Historic Speed Figures?

I was just wondering if anybody has ever gone back through history and calculated speed figures. Beyer, sheets, thoro, anything? I would love to see some of the numbers the great horses through history have put up. It would also be fun to see if some big upset wasn't really an upset on paper (seabiscuit v. war admiral). I thought I remember hearing a few years ago that Secretariat ran a 135 Beyer in the Belmont, any thoughts?