"You can move the needle on other than the earliest speedos, in my
experience. It is a little tricky."

I did this when I put white faces on my gauges. I modified a small needle nose plier that has the "hook" on the end. Filed the nose of the plier so it was thin enough to slide between the underside center piece of the needle and the gauge face, then levered the needle up and off by pushing down and out on the plier. Two butter knives can also be used to pop the needle off. You want directly "up" pressure, not any side pressure. Keep your eyes real open for where the needle may wind up ... it can really go flying, especially if you're in a shop with lotsa little hiding places around. Worked well but I can see how that can risk breaking the steel center shaft that the needle slides onto. My opinion is that you'd be guessing about how far to rotate it "back" to accommodate the speedo error, but it may be quite a bit closer than the error is now.

bob