I'm starting this thread as mainly a central info depository for those wanting to install a higher output, later model Denso alternator on their slant.

I kept waffling back and forth between installing a later Denso alt and a GM style 3-wire 12si alt. With bracketry now pretty much unavailable (and my pretty much nonexistant fabrication skills), I settled on converting to a later Denso alt from a later model Mopar vehicle. I'm using a '90 Dodge Caravan as a parts car reference so I've got something to tell the counter croney at the local junk yard.

EDIT: I'll be using an '89 Diplomat as the reference, as they're shown to come with a V-belt pulley as opposed to the serpentine pulley.

I'll be using a 90 amp unit (120 seems like a bit of overkill) and like I did with my truck, will use 2AWG welding cable with soldered-on lugs for my charging wire. The regulator to use is Standard-Bluestreak P/N VR125. Many Mopars from the late '80s-up had the voltage regulator integrated into the computer, so your best bet is to find the reference P/N. You can, however use the '89 Diplomat reference to get an external regulator at a parts store, as I'm told they used external VRs as well. The electronic dual-field regulator is presumably compatible with all Chrysler alternators.

Also, to upgrade to 90A or the 120, it's going to be MANDATORY to do the ammeter bypass and update the charging wiring, due to safety.

To physically install the alternator, you'll have to shave about 1/8" off the front of the front "ear" of the engine's alternator mount. This is based on info I've gathered, and not from personal experience. I'll find out for sure when I do the conversion myself. Apparently this shaving is all you'll need to do, and the pulley should line right up.

If anyone has any other info (or corrections) feel free to post 'em up. I'll be sure to post updates as I do the conversion myself so it can be as streamlined a process as well for anyone else doing the conversion in the future.

UPDATE: For those of you wondering which leads on the alternator to connect to which leads on the voltage regulator, this is a quote from Dan (SlantSixDan) from a ways down in this thread:
There is no positive or negative field. It doesn't matter which field will get which field wire (or, if you're still using a '69-down "single field" type regulator, which field will get hooked to the regulator and which field will be grounded). These alternators all use a small-diameter threaded stud connector for each field. There are spade-adaptor terminals reasonably easily available if you want to retain the spade connectors on the end(s) of the field wire(s).

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'74 Duster w/ HEI ignition, beat to snot suspension, A904, 8.25" 3.55 SG rear, still being tuned up and gets 17 MPG

Know how they always build a better idiot? That's me

Excellent thread... I have to do this on my '68 Dart.

Are you using the Diode setup for bypassing your Ammeter?

Also, I believe that there is actually an alternator mount adapter out there for those who wish to purchase it rather than build it.

When you get this completed and running it should go into the "Articles" section. Please make a page for it... or send me your photos as it happens and I'll be happy to make one.

-Mac

I'll use a voltmeter instead of an ammeter, so I won't need to worry about diodes at all. I prefer a voltmeter, so that's what I'll go with. I'll have the larger gauge lead still going under the dash to power my gauges, radio, etc. but at some point that'll all be rewired and hopefully cleaned up quite a bit. It's pretty wrecked under there.

As far as pics, I'll post 'em as I do the conversion. I don't forsee any problems or hangups yet, but I'm sure I'll run into a couple once I start doing the work. I'll do all the wiring upgrades first, then once I've got it all set up to handle the higher power, I'll install the new alternator. I figure safety first, then power.

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'74 Duster w/ HEI ignition, beat to snot suspension, A904, 8.25" 3.55 SG rear, still being tuned up and gets 17 MPG

Know how they always build a better idiot? That's me

My 89 Diplomat had that same alternator except its pulley was a V instead of a multi rib as the Caravan (serpentine) had. It also had the '70- up Mopar VR, NOT computer controlled; Ive seen this setup as well on diesel trucks til at least '95. When the alternator died on the Dip I went to the junkyard and got one from a Daytona, forget the year, with a pulley swap I was good as new. This is just to let you guys know that they DID use this same alt from the factory with an external reg. I believe 88&89 Dip Gr Fury-5th Avenue all had this setup. My 88 D 100 and my 90 Dakota also used this alternator as well, but they were computer regulated like your 90 Caravan example.

Good tip on the '89 Diplomat reference. According to Rockauto it's also available in 90A and 120A flavors and comes with a V belt pulley. Guess that's a bit easier than sourcing a Caravan alt and swapping pulleys.

I wonder what dictated a car getting a 120A version Vs. a 90A version. A/C maybe?

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'74 Duster w/ HEI ignition, beat to snot suspension, A904, 8.25" 3.55 SG rear, still being tuned up and gets 17 MPG

Know how they always build a better idiot? That's me

I woulda thought being cop/taxi, but yet mine was an ex squad with the whole package, but had a 90 A. as did my 88 D 100 with the same alt. Maybe it came with a 120 and had gotten replaced with whatever was on the shelf at some time before I got the car.

Like Don said, probably Cop/Taxi. I know the cop car I parted had a 120A alternator. Still have it in storage, if you want to mess with it. Pretty big and bulky, though.

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'15 Chrysler 200S V6
'74 Duster 360, factory 4 speed car

Just to flesh-out the availability info: The 40/90 and 50/120 alternators were supplied by Bosch and Nippondenso as well as made in-house by Chrysler. All three are significantly different in design, overall size, and overall weight, but as long as there's nothing physically in the way, all of them of a given intended application mount-up the same. The Nippondenso is smallest and lightest. All of them have a good reputation for durability and performance. All of them were available with 4-rib, 5-rib, possibly 6-rib (not sure) and V-belt pulleys. All of them have the same electrical connections.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

Good call, Dan. I noticed the pictures of the different manufacutres units differed on Rockauto, but I was thinking it was just different units altogether being used for a photo reference.

Something I noticed though, is that it seems they have a type of connector on the back, as opposed to spade terminals on older style alternators. Is there any way of telling for sure which lead on the connector is for the positive (IGN switched) field and which is for the negative field? I'd hate to set up the wires backwards and then end up toasting something...

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'74 Duster w/ HEI ignition, beat to snot suspension, A904, 8.25" 3.55 SG rear, still being tuned up and gets 17 MPG

Know how they always build a better idiot? That's me

There is no positive or negative field. It doesn't matter which field will get which field wire (or, if you're still using a '69-down "single field" type regulator, which field will get hooked to the regulator and which field will be grounded). These alternators all use a small-diameter threaded stud connector for each field. There are spade-adaptor terminals reasonably easily available if you want to retain the spade connectors on the end(s) of the field wire(s).

Oh yeah, and these alternators are used on most all '89-up Chrysler products, but again, you need to make sure that the mounting and pulley configuration suits your application.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

No kiddin, huh? Well I guess that makes it easier to fab up an easy wiring harness without worry of wiring anything wrong.

I have a feeling this'll be a good writeup once my conversion is done and I've had time to do up the article.

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'74 Duster w/ HEI ignition, beat to snot suspension, A904, 8.25" 3.55 SG rear, still being tuned up and gets 17 MPG

Know how they always build a better idiot? That's me

Okay bringing this thread back to the top, since I'm hopefully going to be pulling the Duster out of the garage this weekend and working on the conversion once I get the water pump changed (ugh).

For those of you using a voltmeter with a dual field system, what lead do you have the gauge connected to for an accurate reading? I would expect just the IGN1 circuit coming off the ignition switch would work just fine.

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'74 Duster w/ HEI ignition, beat to snot suspension, A904, 8.25" 3.55 SG rear, still being tuned up and gets 17 MPG

Know how they always build a better idiot? That's me

What is the advantage of the newer alternator over the original that came in the '74 car? Is it lighter? Less drag on the engine? Fill me in. thanks

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Grandpa's 1974 Dart Custom 4 door 225 auto, Aluminum Radiator, 1920 Holley.

Higher amperage available. 90 (or 120 if you choose) amps versus the original 35 amps. Better capability to run electronic ignition, upgraded headlights, a good stereo system, electric fuel pump, etc...

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'74 Duster w/ HEI ignition, beat to snot suspension, A904, 8.25" 3.55 SG rear, still being tuned up and gets 17 MPG

Know how they always build a better idiot? That's me

...better output at idle and low engine speeds...

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一期一会
Too many people who were born on third base actually believe they've hit a triple.