When I started racing, the old Irwindale was using an electric pen to write down 1/4mile e.t., and mph, (from the tower Chrondecks) and half the time you couldn't read it. And that was ALL you got. Early 70s.
I went looking a few months back to see if I could find some of those old electric pen slips, but the oldest I could find were from the eighties..... from FIVE tracks that don't exist anymore.