Want to improve ignition....
Best bang for your buck is curve whatever distributor to your application.
Absolutely! And for this situation, curving the original Chrysler distributor is the best option for street and strip.
Getting the curve right is far more important than having the potential for increasing spark voltage, and increasing energy.
Since your car was a smogger, the simplest way is to
shorten the inside of the slots. Then tweak the spring tensions.
Alternatively, have someone set it up who has a selection of springs and cam plates.
Halifaxhops can do that.
73 dart swinger / 360 with a big purple cam and true 2 1/2” straight exhaust, edelvrock performer intake and Holley 4bbl carb.
It would be better to know which purple cam, but that's a situation a MSD 6A, 6T or 6C would be good for. (6C is no longer made - you'ld have to buy one used).
A multi-spark CD ignition has a better chance of firing in poor combustion chamber conditions which you can pretty much count on at idle and low rpm with a cam like that.
At higher compression conditions at high rpm (5000 up) it also does well.
Of course the better you can make the combusion chamber conditions, the less need for an system that can multispark and produce higher voltage.
A good HEI module may also be a little better than stock with your purple cam. It's still an inductive ignition. CD ignitions produce a short spark duration. Inductive igntions produce a longer duration spark. Some evidence indicates a long high energy spark may work better with today's pump 'gasoline' when there's not enpough heat in the chamber to build a good flame.
HEI module's regulate the current to the coil. This is the job of a ballast resister in other inductive systems. An HEI can be, and maybe should be, paired with an e-core coil with appropriate primary resistance.
CD systems regulate internally as they build the primary energy in their box, and then send it through the coil. CD systems should be matched to a coil with appropriate resistance to take advantage of its characteristics. (and also not get cooked).
