[tubman]

You want some resistance on the primary windings, say 6 or 8 ohms. On the secondary, you want to see 15,000 to 20,000 ohms, maybe even higher. You may be reading the wrong scale on the ohmmeter. Since resistance can vary so much, most meters have variable scales. There is usually a knob or something to switch between them. Testing the primary while set to a high scale can make it appear that there is zero. There has to be some primary (and secondary) resistance, since you are getting spark.

Since that is an aftermarket coil, there's no telling how old it is. Most original Ford coils have long since given up the ghost due to age. They can be renewed.