Is there a voltage regulator out there that will provide a more consistant voltage, say between 13 and 13.5, rather than dropping to 11 or 12 when lights are on and at idle, and coming up to around 13 once engine speed increases? This would be on a 73 A body.

It is not a regulator problem, It is that the alternator is not puttingout enough to compensate for the draw at idle. It will help some if you put a smaller pulley on the alternator or better still upgrade to a later higher amp dual field hook up alternator system.

A 73 A-body would be a dual field alternator. Pick up a MP blue regulator....P3690731. That will give you a constant 13.5 volts. Youll have some people telling you not to run one on the street, but Ive been running them for over 10 years on everything I own. Im not the only one. It couldnt hurt to look at the alternator, but that regulator is what youre looking for if you want to maintain a constant voltage

OOPs missed that. But still very likely has the lowest output alternator still available. Many were used in low optioned cars.

to the origianl poster.
I have one of these blue constant voltage regulators on hand still in the box. you can have it, just pm me an address I'll send it to you.

Current and voltage are two different things. How does a high amp alternator prevent low voltage at idle? I'm thinking that the alternators are the same physical size. In order to flow more current, the wiring needs to be larger, thus reducing the number of windings in a given space, reducing the voltage generated per revolution within a given magnetic field.

Actually a complicated subject. So, some quick facts:

> All else being equal, a "larger" (higher output ampere rating) alternator will increase voltage at the below-full-regulated-voltage RPM.

> Below this RPM, the regulator, if working properly, should be virtually "full fielding" the alternator.

> Reduced output is a symptom frequently caused by one (or more) bad diodes in the regulator.

> A smaller pulley does, indeed, increase low-RPM output. However, 1G Chrysler alternators don't live very long at high RPM (part of the rationale behind large pulleys on race Mopars). A better fix is a 65A. alternator with a larger pulley.

> All voltage regulator used on the street should be temperature compensated. Constant-voltage regulators run the risk of cooking the battery in hot weather and actually undercharging in cold weather.

> Internal regulators, e.g.: GM, are lousy at temperature compensation

> Most late-model Mopars actually vary the voltage in response to the battery temperature -- that's as good as it gets.

Rick

There is some evidence that the last few years of the 1G Chrysler (Indy built) alternators (1960-up style) were ruggedized because they were also used on 2.2Ls.

Rick