cranks but no spark at coil

Steve I did not read quite all of this. Your starter relay is different than your Cuda. On that relay, there is a terminal that provides fire to the ignition when cranking. Put your meter on coil+ and crank it with the key, you should have "same as battery."

If you have that, next turn the key to run, take the engine harness end of the distributor connector, and tap the bare terminal on a good ground. It should make one single "pop" spark each time you do that.

If those two things work, make SURE you clean the dist. connector, and if no joy I'd start looking for a pickup or other distributor.

Check reluctor gap?

Spin dist. with multimeter hooked to dist, on "AC VOLTS?"