So much fun and so little to understand. "Dwell" what is it? Actually a rough measurement for coil saturation. The magnetic field must build up and then collapse. Spark!. The points are...a switch. On-off. Points closed? Current in coil, field builds.. Points open? Field collapses, spark. Fancy word for this is..induction. So, dwell angle. Camshaft way to say, "how many degrees are the points closed. That depends on a few things. 1, shape of the cam.How much lift is there and what is the ramp? Camshaft stuff. Can points "bounce"? Yes. So, the shape matters. 2, How many times will that switch open and close for a given amount of time? and how long will that switch be closed? Depends. How much current will the switch handle? How much will the coil take? An amusing observation: 4 cylinders? 45 degrees dwell. 6 cylinders? 40 degrees dwell. 8 cylinders? 30-35 degrees dwell. Notice anything? Back to #1, Point gap matters. So far Hotrod has the practical grasp. You and me get to work with what the Engineer and the Manufacture gave us. So, sometime in the distant past, some guy with a slide rule found out how much current the switch that the Accountant let him use would take over time. Sneaky guy he was, he added a Capacitor(Condenser for us car/truck folks) Just a few pennies he got past that Accountant. So, for a simple recap, the cam shape depends on the Dist. PN. Hotrod got that too. Now on, to coils. . Some guy had to figure how many turns and how big the wire was gonna be in the coild(Enter Mr Accountant again) Moe math and more current calculations, Done. For a 4 cyl motor. Mr accountant approves. Then someone said 6 cyl, and instead of more math, we just, use the same coil and switch. Now someone gets creative. 8 cyl and 12 volts. Take that Mr. Accountant. So we get The "Ballast" resistor. Current is controlled. Switch still works and no money was spent on Math. Then someone decided to put that resistor inside the coil. And we start the confusion all over again. Now we have a true 12 volt coil. May your morning be well caffeinated. Enjoy. Shout out to Hotrod. Just set the gap according to the PN. You got it.
