Could my 340 block be filled?

Sorry to hear about this. But it can be fixed. Let's take some troublehooting steps rather than just throwing parts at it.
1) I notice that your ballast connections are corroded a bit. Based on where you live, it would be pretty common to have erratic connections. They can be in the firewall connector, or even back at the ignition switch. Get a decent voltmeter, and make a measurement of voltage at the ballast with the car running; the voltage at the terminal with the blue wires should be no more than 0.5 volts lower than the voltage across the battery terminals when running. If it is lower than that, then you have voltage drop in the connections and wiring that needs to be traced back and fixed. Check this when it first starts as well for a reference.
2) I see the ballast that you got; can you tell me the brand and model? I have some in that shape that are wrong for the Mopar system; they have high resistance and they will drop the spark energy a LOT. So that need to be checked; the shape is a possible clue but the PN is needed to know for sure..
3) Which model of MSD coil do you have? Again, coil primary resistance is important for this system.