225 Slant Six Crank but Won't Start (Fuel but No Spark, Dist. Rotor turns)

Please help me. I have 1970 Plymouth Duster that will crank but won't start. The parts I have replaced are: Starter, relay, coil, and spark plugs.

I took spark plug out and tested but am not getting spark. I also took distributor cap off and can see the rotor turning. I don't know what else it could be??

So to recap.. the car cranks and I'm getting fuel but NO spark.

Thank you for any help I have been go ogling and trying to fix this car for weeks. It's starting to drive me up the wall!