Used to call them cotter pins when i worked as a motor mechanic (a while back) may be able to get them from Repco,Auto One,Soua Cheap etc.
If you cant find one I may have one in my spare Bally spares box.
High Tap ? I did it on my Gottlieb Sweet Hearts as the bumpers & coils were a lot sluggish compared to the Bally.
Hasnt broken anything yet.
You will find Bally used 50v Coils which gave those bumpers etc more oomph, so I wouldnt touch the voltages.
