But, how to do that. I tried putting a dab of white out, my favorite indexing medium, on the tube and the corresponding rear side of the the ignition lock body, but that was imprecise and the mark on the tube got worn off when I pulled the tube out to access the switch. I think it might be better to use a spring-loaded center punch to put a mark on the side of the tube and then use a Sharpie to put a corresponding mark on the grey ignition interlock donut. That would give you fighting chance of getting things close. From there, it's just a matter of jiggling things around. Again, my problem stemmed from two things: First, I didn't initially realize that the key had to be pulled from the ignition in order for the spring-loaded interlock pin to engage. Also, that pesky cap screw locking bolt was hitting the bottom of the dash and preventing me from getting it forward enough to jiggle. The car had been restored, so the factory relationships of everything were disturbed. Once I pulled the key and cut a u-shaped notch in the bottom of the dash to clear that screw, the jiggling process was pretty successful.