The two coil problems I have experienced with the Mallory coils:
A couple of years ago the car would sound fine in the pits and burnout. It would leave soft, not rev very good, and then fall really flat after the shift. It just hated the load, and each gear it was worse.
2-weeks ago, the coil seemed ok 1st run, although it blubbered just before the shift at the top of low. Then no fire for the 2nd round. No other warning just quit.
For what it is worth,