Biggest distributor issue I find
The biggest problem I find, in well kept, or NOS mopar electronic distributors is timing variation between cylinders. The timing variation is due to nature of variable reluctance trigger, and the errors resulting from runout, remnant magnitization of the reluctor, and crude manufacturing tolerance specs.
The timing variation varies, and is a few degrees. Most ignore, it gives a waver sound to an engine. Many more problems result , but that is up to creative tuners to ponder.
I know of this by using electronic means to measure the precise timing between ignition trigger events. At constant RPM, trigger events should be 90 degrees apart for a V8.
Halifaxhops, I can make a device that measures cylinder timing variations, and gift it to you, for use on your machine. But be warned, improving the stock distributors will not be worth the precious time. The cut down performance reluctors, should help some, along with runout reduction.