1978 Ford Thunderbird no spark to plug wires

So you sound like you have replaced plugs, wires, distributor and coil. Ignition control module? Make sure that this box is replaced. If you tried all of this then good chance you have a short in the wiring. Find a good digital multimeter at your parts or hardware store $25-30. Check the hot white and it must be the same as battery, 12V, +/- .2V. Check the red lead from the ignition to the ignition module with the ignition on. 12V +/- 1.5V is within tolerance. Check all your grounds and make sure they are good. The coil should recieve 10-12V if the ignition switch is on between the two terminals.