When all else seams to fail start at the beginning to resolve problem.
1. Check the Ditributer Rotor, GM rotors were notorious for burning a hole through the rotor, you will have to pull off and look underneath of it, if you see a black burnt spot, this will do it..I have seen new rotors burn through in what seems likee no time at all.
2. Make sure you have voltage to Distributer and disconnect Tach to eliminate possible issue,
3. You replaced coil (new Coil?) under the HEI cap, which there should also be a ground under the coil,
4. Check cap to make sure the center elctrode is there, you should have gotten new one with coil and replaced as well.
5. check when you are cranking engine the 12 volt lead to distributer has voltage while cranking.
6. The plugin from distributer to cap is also plugged in.
7. DOuble check grounds, run jumper cable from frame to engine and Negative battery terminal to frame.
7. If still no spark. You have a serous problem.
