Continued good input, thanks again.
It's the same tank of fuel as when it was running perfect. I only use Chevron fuel (it's the only consistent brand out this way). I mix a little MMO in the fuel at each fillup. The tank is now between 1/2 and 3/4 full, and it gets topped off at each fillup, so it ran for over 30 miles perfectly on that tank, then started acting up just yesterday morning.
Fred- Does the same thing with the older cap on it. And, I did check to make sure there was no arcing between any strap and anything else after taking the plugs out and cleaning them. I remember having that same problem once a long time ago, and bougt another new cap because of it. This is a similar symptom, but likely a different cause.
Marco- I respect your opinion. Perhaps I'll start with the distributor and use the same wiring and coil just to satisfy our curiosity. As you mentioned, confidence in the car is the issue. That's why I just wanted to shotgun the whole electrical system. The goal is to get a reliable car, not one that is always questionable from day to day. That is unacceptable.
Louis- Unlike most people here, this isn't my hobby or toy. We rely on this car for transportation. It has to be reliable and dependable. If it isn't, I will have a very difficult time justifying keeping it. I let go of a 69 Charger to get the Model A, and don't need any more "told you so" sarcasm out of my family. We use our car, we don't "play" with it. That makes these intermittent problems much more important to solve and move on quickly, and not spend weeks fiddling with it. Does that help explain the "shotgun it" method of procedure?