[Peter Serio]

1001 RPM at 60 MPH yes for the odometer to count over 1 mile. We are not dealing with something calibrated to land on Mars.

None of the passenger car speedometers were ever that close to start with. In fact if you look into any of those old Road & track or Autoweekly magazine road tests you will see that GM delivered all new cars with the speedometer's reading greater than actual. Over the life of the car the magnetic strength looses energy so each year the speedometer would read a little less MPH. Often they were magnetized up to strength to read 10 or 11 MPH greater than actual. During the "life" of the car each year the magnet (actually a piece of grey iron) would loose a tiny bit of it's strength so you can in all of those old road tests where they put a Weston Electric speedometer in the car ( a 10 speed bicycle wheel & tire) clamped to the rear bumper. All GM cars & trucks, their speedometers were calibrated to read higher than actual in the beginning and then over the normal life of the car they settle down bit by bit.

Back then it was expected the car would run for about 10 or 12 years ( driven every day) and in that amount of time the car would accrue at least 100,000 and perhaps more miles.