No spark at coil

Just like "superchargeddrt" II also think you have a gound somewhere. From what I've read here, it would have to be after the Ballast. Which is pretty much all the stuff you probably hate to work on. Any of the components after the ballast could be smoked & be providing a ground...but here are some other thoughts.

Are you using a coil that requires an external ballast resistor? They are available with an internal resistor.

The 440 doesn't mean anything when working on this.

Is this a new project or were you driving the cars for weeks then it just quit?

Is your pick-up in the distrib working? You should be able to put an ohms meter across the leads & "see" a pulse as it tries to fire each cylinder.

The ballast can get very warm. When the ballast gets warm, it's telling you that it is working. Not all ballasts have the same resistance. The higher the resistance the more heat it will make.

You shouldn't have 12v at the coil unless the ignition is on...did I read that wrong? Disconnect the neg side of the coil with the ignition on...what do you get? Should be less than 12 & more than 5 depending on the ballast you have installed. Unless your coil has an internal Ballast...then 12.

Is your ECU grounded? It should be. I assume that it is because the ballast is heating up.

This may not be true for you particular model...When in the start position, the voltage comes from the starter rather than the ignition switch. Then when you let go of the key it is applied from the ignition switch "On" position. To troubleshoot this...turn the key on then "jump" the starter at the seloniod.