Marko's sinister black ragtop is all business with a stout solid-cammed 7,000-rpm 340 coup
Do you own a '69-or-earlier Mopar musclecar? Unless it has already been upgraded, the charging system consists of the old "weak sister" single-field alternator and its accompanying mechanical points-style voltage regulator. Ever wonder why those lights dim when the engine's at idle? With only 35 amps max output in standard V8 form (and 26 amps for sixes), by today's standards these old alternators are pretty feeble. Moreover, at idle the situation is much worse, with the alternator putting out only a fraction of its rated capacity at low rpm.
Due to the slow on/off nature of these old mechanical regulators, the swing from discharge to charge is too wide for many modern electrical components, including Mopar's electronic ignition. The electronic ignition may work, but with the voltage swings inherent in the points regulator, the factory didn't recommend the old-style regulator with the new ignition system. In fact, when electronic ignition made its debut as a production system, Chrysler had already switched to solid-state electronics in the charging system with the electronic voltage regulator and the corresponding dual-field alternator. For racers who wanted to retrofit to the new ignition system, a race-only, constant-voltage regulator was offered through Direct Connection (now Mopar Performance) to make their ignition system compatible with the old charging system. Though you were able to run the constant-voltage regulator on the street, the factory always maintained this regulator wasn't made for continuous duty.
These days, handling the electrical load with power-hungry aftermarket components, such as high-powered ignitions, fuel pumps, electric fans, and the like, will tax the stock charging system well beyond its output, so you may find yourself asking for jumper cables at the next cruise night. Even worse, some ignition systems will simply shut down if the battery's voltage drops too low; not a good look.
OE Mopar alternators were continuously upgraded throughout the years, both in max-rated capacity and low-speed charging ability. In 1985 the Chrysler alternator was redesigned to produce 78 amps, which was higher than the previous alternators. Starting in 1985 this alternator was used in M-Body Mopars and, with the exception of the narrow center band, was similar in appearance to the older alternators. Though the mounting points and wiring were identical to earlier alternators, the slightly wider body limits the belt adjustment to the outer two thirds of the stock range in most applications. Upgrading to a later version of the Chrysler alternator is a no-brainer mod for '70-and-later cars already equipped with a dual-field alternator. If you have a '69-or-earlier Mopar equipped with a single-field alternator, switching requires some minor changes to the wiring and a swap to the late-model regulator.
What's involved? Certainly, a lot of us would rather tear down the motor and swap cams than deal with the electrical system, but switching from the early-to late-charging system is quite simple. The original mechanical regulator had two wires going to it: a blue ignition-on wire feeding it juice and a green wire going from the regulator to the single-field plug-in at the alternator. Guess what? The solid-state electronic regulator also has a two-wire hookup: a blue ignition-on wire and a green wire going to an alternator field; same-same.
The stock single-field alternator was already a sissy unit and was made worse with the und
Our Chrysler 78-amp replacement alternator (left), like all '70-and-up Mopar units, requir
Up front, the new alternator has a smaller pulley than these on the aftermarket piece on t