I agree J.W. Start with basics cleaning everything including the points bolt to remove any oil, Replace the wires, polish the contacts, junk the caps & check for out of round stater & run a bonding wire, mag to block. I use Super Corona Dope & fine glass cloth to help them also. No problems with my KG7, KF7 or my KH7 all bendix.
And, BTW, when I replaced the first original KG7 coil, I fou9nd that the high tension wire was just twisted at the coil lug, NOT soldered. I continued that practice. Figured Carl knew what he was doing when it came to mags.
I have pulled my hair out agonizing over seemingly all details of Bendix mag woes. When you get one that kicks your butt, after all basics have been checked, run the spark plug gap at .015" and you will most likely be amazed at the results.