I just thought about it.. if he's runnning Pertronix, he wouldn't need a ballast resistor with an aftermarket coil.. My truck isn't running one right now, either.
It depends on both the version of Pertronix used, as well as the coil itself. The Ignitor I requires the resistor to stay in place with a stock coil. Aftermarket (and Ford) coils with internal resistors can be used without the ballast, obviously, but coils like the MSD Blaster 2 often require a second resistor inline with the first.
The only Mopar electronic ignition failure I've ever experienced was attempting to run a gold ECU on the street. It was a murder/suicide, because it took the Blaster 2 (without the secondary resistor) with it. I have never had a single problem with it otherwise, including the "failure prone" ballast resistor that I've never once had to replace. If you know how a ballast resistor actually works, and the reasoning behind it, it's a brilliant piece of engineering and far superior to an internal-resistance coil, such as those used by Ford. Regardless, I always wonder about the condition of wiring in cars belonging to people that tell me Mopar stuff is unreliable. The only electronic part I've had to swap with any kind of regularity is alternators, and never more than once per car. I've never been failed by a stock ECU, resistor, voltage regulator, etc.
Prior to my ownership, my 300 had the ESA disconnected and the distributor replaced with a points unit. Whomever did that swap wired the ignition coil to an accessory terminal for some stupid reason. With the key turned backward so I could listen to the radio, it fried the points. They would
not get me home. Points suck. They do not have a single advantage over electronic ignition other than resistance to EMP. So, if you've got a nuclear warhead detonating nearby whilst driving, the car will stall but restart. It won't be an issue, though, since you'll be vapor and ash at that point.
My boo-boo on the electronic ignition. It was optional in
'72, being standard only on the high-performance engines, high-end Chrysler models and Imperial that year, since points are especially worthless on a performance car, and a premium car should start more quickly and reliably. It became standard across the board in '73.
1973 Dodge Dart - $10,950 - 147 Concord Road, MA - 1973 Dodge Dart - Nice dart sport just up from Florida!! This dart has a healthy sounding 340 with headers, and automatic transmission. The exterior is white with the sport stripe down the side, a black hood scoop, and silver painted bumpers give this hot-rod a custom flair. Its got a nicely detailed engine bay, and clean interior. This car is a nice driver quality car that gets thumbs up wherever you take it!! 
