Refer to the wiring diagram, click here
. First of all, you should have battery voltage at the pink wire to the coil with key on start or run. The pink wire coming from the ignition switch, not the pink wire from coil to distributor, although you may have voltage there as well. Second, the white wire for the tach you should be checking with a 12 volt test light while cranking. That should flicker if the primary circuit is ok.Quite possibly the other white wire may flicker also, according to the diagram.
Anyhow, how are you checking for spark and are you checking right at the coil? If so, swap a small spark plug wire for the coil wire and check again for spark at the end of the wire.
Make a test plug. You can make a test plug with a new spark plug and some wire, a mini hose clamp and an alligator clip. First open the spark plug gap to around 0.075" and strip both ends of a 16 gauge wire about 4 foot in length. Attach the mini hose clamp around the threads of the spark plug cause that is a ground and secure it with the mini hose clamp with the bare wire end in between to make a good connection. Next, take the other end of wire and secure to an alligator clip.
Now, you have a test plug. Remove any spark plug boot you want and insert your test plug onto the spark plug wire end you just pulled off and ground the alligator clip. Lay the spark plug in some shade somewhere under that hood and then crank the engine and look for spark. It should crackle with sound and should be blue but red is ok, orange is a little weak. If it can jump that 0.075" gap you should have no problem igniting an engine.
You can also use that to check coils on some vehicles.
Hope this helps.