I have a stock alternator on my 73 Challenger and I would like to change it to a larger 100 amp type alternator .My question other than it fitting, is the field wiring the same?

Depends on which 100A alternator you are using. If it's a Chrysler one then yes.

Depends on the alternator you choose, some high-output alternators wire just like the original single and dual field terminal units.

http://www.qualitypowerauto.com/item_557/Chrysler-Mount-Mega-Amp-Alternator.htm

It seems to be a Chrysler part,the two field connectors are stacked one on top of the other.i will post pics when I figure out how to do that it’s been a while since I’ve been here on the side

Might want to read this
https://www.allpar.com/history/mopar/electrical.html

That's a Chrysler 117A unit, works the same.

agreed, read the allpar sheet, you want all your voltage drops minimal (clean all terminals/connections including ground paths & grab your meter). On a side note there are 2 pulley sizes on our alts that I have seen (I forget the measurements) and you might have the larger one & a swap to a smaller one would help (not sure how much) tho it would involve splitting the halves & haveing a shop R&R the old new pulleys. EDIT the one in the pic is that a Leece Neville? I have one of em with the special bracketry for it. MORE EDIT with some easy math you could figure the additional alt speed you would gain from the pulley swap. Then what general RPM "range" are you in now where there is inadequate charging/will the pulley swap get the alt pulley RPM above that & into an "adequate" charging range" for a sufficient % of your driveing time to take care of the issue (& checking/cleaning terminals as needed) or if a better alt is needed. Relays get very good reviews (for heater/headlights/AC). 2&3/4" and 3&3/4" vaguely comes to mind on pulley dia's but I ain't sure.

The alternator pictured is a Leece-Neville, common on cop cars of the sixties/seventies; takes a special regulator.

John you ARE the man! what reg does it take & where is the other field terminal?

Stacked one atop the other

Thanks everyone I am left with more information and still lost?

I ran one of those for a couple years on my 87 Diplomat, retrofitted it, using the normal regulator, worked just fine.

Yes I see it now! & that is good to hear a "regular" reg will suffice. Thank you!

Keep posting with any & all Q's (no matter how mundane) as that is what we (& Moparts) are here for.

those bigun's take a special bracket. if you are putting one on a big block, i have a bracket setup for a 440 i'm never gonna use. PM me if interested.

I run that alternator on a B big block. I started with a 75 amp square back but not enough output for EFI and EFI fuel pump. I had the big alternator and special bracket from my core engine.

On the plus side, it has plenty of idle output. Works great in that respect. Downside is weight... very heavy. Last I checked reman replacements are available for service... though a reman on a 40 YO core may be iffy.

It works fine on a standard replacement regulator.

If U are going to run a high amperage alternator, U should consider upgrading the wiring harness...

Just my $0.02...

Or more precisely, if the equipment is being added where the loads require that alternator, then the wiring should be matched to the new loads.

ahy's setup is such an example.

Agree with the comments on upgrading wiring with a big alternator. I run a 6 gauge charge wire from alternator to the battery main cable. No charge current passing through the bulkhead connector. The ammeter in the Rally cluster was stealth converted to a voltmeter.

Most Mopars through the 60's and 70's used either the mechanical reg with a single field wire and a grounded brush or the electronic 2 pin reg and the dual field grounded at the reg. But some Imperial's used this system here on the link which is not seen alot as even working 24 years at a Dodge dealer I rarely saw this. This is the 3 pin voltage reg and this setup has a 12 volts fed to one field brush all the time from the rectifier inside the alt. It still controls the ground at the reg but the field wire at the reg is hot even with the ign key off. That's why this uses the ign 12 volt to power up the reg and has a battery volt feed to the reg to check battery volts where the 2 pin electronic reg uses 12 volts through the key on ign to check battery volts. If by chance anyone ever uses this style alt it has to use the right 3 pin reg. Ron

http://www.imperialclub.com/Repair/Lit/Master/256/back.htm