Mopar electronic ignition with 1.5 ohm flame thrower coil

Yes, that is what I would recommend for coil durability; the Mopar electronic system used a ballast with the same style of canister coil and and the same 1.5 ohm coil primary resistance. (BTW, I am going from memory on why I decided that was the right way to do it with this coil; I can't find my set of those instructions to double-check.)

Make sure it is a Mopar OEM ballast or an MSD one with 0.8 ohm cold resistance. Many other ballasts have too high a resistance.
So adding the ballast will help protect the coil