In Reply to: Spark update posted by Roger on March 17, 2017 at 18:55:43:
" the spark noticeably hotter on the test light"
An adjustable gap spark checker is a far more reliable method of checking spark.
What made it start was the act of replacing the coil......and not the new coil itself. It's loose on the distributor or the pigtail is grounding. Or you have a bad wire or connection.
Next time it stops, check immediately (not 5 minutes later) for battery voltage at the top of the coil. If you have voltage there, check for spark. No spark means the problem is in the distributor.
Replace the gasket under the coil. It should be a struggle to get the bail over the coil. If it's loose, it won't make a solid connection.
Remove the distributor. Take the cap off and install the coil. The coil should have no movement and the pig tail should be firmly seated in the brass concave head screw. Did you set the timing ? Sometimes that results in the plate getting turned so far that the pigtail looses contact.