I haven't had a chance to work on it again yet, but yeah, I thought of disconnecting the alternator.Easy to rule out. Disconnect the Alternator and run on a good charged battery with no other electrical accessories running. Surely you can run it long enough to see. I am still suspect of voltage at the coil and polarity correct and then perhaps a faulty coil at temperature. I like Mallory stuff myself. They have been quality for the 40 plus years I've bought it and the older stuff is no different.
How would I check for polarity?