There is an air gap between the rotor and pickup, in the distributor, it needs to be set at .004" If the g is wider than that, no spark. The gap widens as the distributor gets warm, so sometimes you'll get a car that will start cold but not hot.
A '72 scamp came with a factory thermostat of 195 degrees F.
Assuming you kept the stock thermostat middle of the gauge should be about 195. I had a '72 Plymouth Satellite and when I had a 160 degree thermostat the gauge stayed close to the cool end of the scale. When I put the correct...
Hmmm, interesting. Was that .008 Hot? I know that the gap will open up when hot, that is why a car might start fine cold but not start hot.
Back in the late 80s I converted my car to a Stinger Electronic Ignition kit, but I used a stock Chrysler distributor with their electronics box...
CHECK THE AIR GAP as suggested above.
On mopar Electronic Ignition it is set at .004, the above poster recommends .008. VERY IMPORTANT USE A BRASS FEELER GAUGE, a steel feeler gauge will be attracted to the magnet and make it SEEM like the gap is correct when it is not.
If the gap is not...