crank no start

I read where you said the voltage at the coil is 6V with the key in the run position. What is the voltage at the coil when you are cranking the engine? It should be noticeably more than 6V. The higher voltage while cranking aids in starting the engine. You have essentially two circuits feeding your coil. The "run circuit" goes thru the ballast resistor and drops the 12V down to (in your case) the 6V you measured earlier. The "start circuit" does not go through the ballast resistor, that resistor is bypassed while cranking so that you can get more voltage to the coil for starting.

What does it read while cranking?