So why the difference in these common lower points.
1. Was this just different manufacturers/different vintage?
2. What design improvement does this represent if any?
3. Is there a performance difference between the two styles?
Also, what is the story on the lower brass style? Was this from an older brass top type coil?
Not sure I remember correctly but the ones with the hole in the head area are KWs. I think the others are from another popular manufacturer, Kingston out of Kokomo, IN.
answer to your last question: "yes"
tension/amperage is adjustable without having to bend the mounting bracket