Alternator compatibility with YearOne engine harness

[Gross Polluter]

I have a 1970 383 Challenger and the engine harness is working but the previous owner sliced and diced it up pretty ugly so I want to get a new one from YearOne, but electrical is not my strong suit and I want to make sure it will be compatible.  My existing alternator has three terminals (one terminal has two wires connected to it).  The ignition was converted to electric with a 90's vintage mopar kit.  The ballast has two terminals. 

Will the Year One harness HU107EM be a plug and play?  Or is there something else I should be considering?  Thanks much!

[moreparts]

I have a '70 383 Challenger too.  I'll try to help.  The Ballast should have 2 terminals as you describe.  The alternator should have 2 field terminals, one with one wire going to it and the other with 2 wires going to it.  Then you should have a stud which is the output power your alternator is generating labeled battery.  That describes the factory setup.  You describe having an alternator with 3 terminals and a stud.  Hopefully you're mistaken because that wiring harness won't accommodate for that.  The description of that harness is to accommodate your Electronic ignition setup if it was done with factory style Chrysler components.  That sounds like what you have for the ignition side of things, but that alternator wiring sounds like it won't be accommodated for. 

If it were me I'd probably opt for a new factory style harness, and get a new Power Master 2 terminal round back alternator to match if your alternator really does have more than 2 Field terminals.  I'd also get a Pertronix electronic Ignition kit or a new Pertronix distributor to put things looking close to factory and clean up the firewall too. That way you could ditch the control module on your firewall. If you decided to do that you'd have to gut your ballast and run a straight wire between the two terminals.  If you went with this setup you'd look very close to factory and still have the luxury of electronic ignition. 

Replacing a harness isn't really all that difficult.  And if your putting things back to factory instead of having to figure out what the previous owners have done that'll even make it easier.

[Gross Polluter]

Thanks!  The existing alternator has two terminals plus the stud, sorry that wasn't clear.  So that sounds like it should be compatible with the Year One harness then?  And then if/when I wanted to replace the alternator, the Power Master would be the one to get for compatibility with the wiring?

I'll have to look into the Petronix options I guess.  When you say I could get rid of the control existing module, I'd still need one somewhere but I guess you're saying the benefit would be that I could mount the Petronix somewhere other than the firewall? 

[anlauto]

The Petronix goes inside the distributor

[moreparts]

No problem on the alt description.  I'm glad that's the case.  Here's a link to Summit Racing for the 2 wire should you need one in the future.  https://www.summitracing.com/parts/pwm-7018/make/dodge/model/challenger/year/1970  That said, if you already have a 2 wire alternator, and it's working fine no need to upgrade unless yours isn't providing enough juice.  The PM definitely will feed your car.

Regarding the Pertronix, no you wouldn't need a control module mounted anywhere.  That's the beauty with that setup.  It's all under the distributor cap.  I think MSD makes a setup as well.  Some of the MDS and Pertronix models have built in rev limiters as another helpful feature.  The Pertonix and MSD will have a second wire coming out of the distributor case, unlike the 1 wire originals.  That second wire is run to the ballast that you'll have modified with a straight through wire.  That extra wire from the distributor is the only thing that would be visibly different from a stock points setup.

[Gross Polluter]

The Petronix goes inside the distributor

Oh I see.  I saw their control modules but didn't realized their distributors were self contained.