Not an expert here, but I believe if it's not broke, don't fix it. I have been running a duel point Accel distributor along with its Super coil and a second (2) ballast Resistors for over 42 years in my 340 (van). I also have a 69 Swinger 340(in photo) and run the stock Prestolite duel point, with a single Ballast. Only had to change the Ballast Resistors once, each. I just changed the plugs, points, condenser, rotor and cap for the first time (Dart), with over 65,000 miles on those parts. The trick is to change all the ignition parts at the same time. A old or weak part will play on the new ones. Engine "Blow-by" will also have a negative effect on your distributor, weather points or electronic. Some distributor caps have "vents", so be sure you face the opening to the rear so not to allow any contaminants to enter. A engine miss could be just a little water, oil or dirt in the cap. Clean often!!!!!
