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BTW there is a ballace resistor on the ignition system and they can burn out anytime.
The 60's versions of the 225 and its smaller brother had a single resistor. The 70's versions have a duel resistor set-up. It is a white ceramic module mounted to the fire-wall by one bolt. There are two electric connections (one on each side) and each has two electric connections. One of those resistors is used to supply a hotter spark during starting. The other is used during run.
That's a common misconception. The ballast resistor is COMPLETELY bypassed during cranking with direct 12v being fed to the coil instead of through the ballast. The second resistor that was incorporated in the early electronic systems with the "dual ballast resistor" was actually a bias resistor for the big switching power transistor in the electronic control module, and it was always in the circuit both during running and during cranking. Later (circa 1977 or so and onward) electronic modules moved that bias resistor inside the module itself and went back to the same single ballast resistor that the old point ignition systems used- you used to be able to identify those control modules by the fact that they only have 4 pins on the harness connector versus 5 pins on the early electronic module that required the dual ballast. The simple fact is that ALL replacement Chrysler electronic modules built since the 80s have the internal resistor, and so if you put one of those into a dual-resistor car, they just ignore that second resistor paired with the ballast resistor int he ceramic block and use the internal one. Some of them still have 5 pins on the connector, but its not connected to anything. the only time you'll ever run into a problem is if you find a new-old-stock or used electronic module built between 1971 and about 1977 and try to use it with a single ballast. It just won't work in that case because the circuit through the power transistor is broken.
Also, the ballast resistor and control module for Mopars is interchangeable between all engines- Smallblock v8, bigblock v8, slant-6... they all use the same module and ballast resistor.
Here endeth the Chrysler electronic ignition history lesson ;-)
and PS- I've driven ballast-resistor equipped Mopars for somewhere between 400k and half a million miles... I ALWAYS carried a spare ballast resistor, but I NEVER had one fail. Ever. I have had the electronic module die while out on the road (and I usually carried a spare for it too, since its so easy to replace), but I'm the very rare Mopar driver who can say he never lost a ballast resistor.