The factory stock electronic ignition system will work just fine. No real need to go with HEI or other expensive systems. There is no horsepower in ignitions.
The factory systems were installed in many millions of cars with very good service.
I've been running the NOS Mopar distributor and chrome box for over 20 plus years and has worked "flawless" for my 340 all these years .. so I picked up a spare a few years back since these are hard to find ... and they can say what want to but the the new stuff is junk... I'll stick with MADE IN USA on my parts
IMO, the stock Chrysler ignition is pretty dang good and reliable. Especially for just everyday cruising. I agree also, using OEM parts is best. Even if they're 50 years old. It's better than most of the new "stuff".