Replacing my points distributor

The ballast-coil match is confusing. I have a Mopar coil marked "for electronic ignition only". I probably took it from an 80's car or truck in the junkyard (lean burn days?). There are also "ballasted coils" that you feed 12 V ignition directly, but I don't know if that coil is such. Some after-market coils are "ballasted", and I think spec >2 ohm. The Crane XR700 after-market box I have on one car, requires a ballast, as does the original Pertronix Ignitor. With an HEI module, no more ballast concerns. The ballast was only to protect points and the early transistors from damage.