i have a 79 f250 4wd 6.6L thats not getting any spark from the coil. ignition module, ignition switch, starter relay, pick up coil, and coil have all been replaced. i have 11volts going to the positive side of the coil, and the negative side pulses as it should when cranking. i have good power going to the module, but still no spark. help!

Optional Information:
Pre-1981 Ford f250 6.6

Already Tried:
replaced all ignition components