I did this to zero the speedometer. Pull the needle off. Turn on the ignition. The speedometer mechanism will move to zero. Push the needle onto the speedometer slightly, with the point about 1/2 inch below the peg (10 mph mark) in the dial face. That should be about where zero should be. Don't push the needle too far down, because the needle won't be able to pass over the peg. Turn off the ignition and rotate the needle pass the peg. Push the needle down to where it normally rests. Let go. The needle should rest of the peg. When the car gets rolling, the needle will start moving at about 10 mph. It may take a try or two it absolutely spot on. I went through this process when I replaced the elctronic guts of my speedometer. I got the needle pretty close on the second try. I'm only about 1-2 miles off. I used a tach reading of 2750 in fifth gear (MTX) to check the amount of error. 2750 rpm is about 65 on the highway.
