I had a problem like that with my other car, not a Datto, but still, same stuff. I changed plugs, wires, cap and rotor, (E ign though), no points, but, you said you replaced them, so assuming all that is good, ign switch, check the coil, it could be messed up, making the secondary voltage interrupt...(primary voltage is the electricity for your accesories, 12V, secondary voltage is the by product of the primary voltage inside the coil, primary voltage, through magnetic energy, creates the secondary)...check the coil connections, if all fine, try another coil, from another Datto...(points Datto, Electronic ign coils have more power, will burn down your points)...if still bugging, check the distributor, that was the culprit in my case, a dizzy shaft that had too much play, jumping the ignition, backfiring, and even turning off the car. A new dizzy cured the problem, I got an MSD billet, the only option I got on a 75 jeep,I did not want to use the same crappy stock distributor.
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