Here's my "I'm a big dummy" question for the day (or the hour, depending upon how things are going ):

Are there any functional differences between a "round back" alternator for a '69-earlier and '70-later? Seems like I've seen stuff re: differences in the charging systems (voltage regulators and???) for those year ranges, yet I see Mancini offers a couple of "repro round-back" alternators that are listed to cover all applications prior to 1975.

The main difference is that the early alternator, has one field wire, while the newer has 2.

Some think that the newer alt actually has 2 fields, while the older only one. This is false.

www.davesmopar.com/techreg.htm

The newer ones start to get into higher amperage ratings, than the older ones too.

The pre 70s ground one terminal of the field at the alternator.
The 70s and newer do not have the one field terminal grounded as the voltage regulator provides a variable ground to control output.
A 70s and newer alternator can be easily adapted to work with a pre 70s charging system by simply grounding one field terminal. So if someone is selling an alternator to work on both systems they are likely providing a short ground strap or wire with instructions.

I think you can also use pre'70 brushes (one of which grounds to the case) in a post '70 alt. Does the same thing as the jumper wire. I'm thinking about trying this on a spare alt when I get a chance.

I'm also running an old style (pre'70) electronic voltage regulator, which is cool and should work well with the new alt.

nice... thanks beepbeep.