As far as the neutral safety switch, the wire runs from the start terminal on the ignition switch to the safety switch then down to the starter solenoid. As far as spark, I would bypass everything to check and run a wire from battery positive to the positive side of ignition coil. Then crank the engine to check for spark. If still no spark, you either have a wire grounding out at the distributor, a bad capacitor or points aren't adjusted right. And there's always the coil could be defective. Good luck