Need to upgrade 68 Cuda alternator to high amperage

[DonnieLawson]

After doing some calculations on amp draw on my Cuda , it seems the factory alternator is about 1/3 of what I'm going to need .
It's still in the build process and it seems like it has been forever...
It's time to get some more things underway....


But here goes....

505 stroker with
2 13" Spal fans for radiator cooling 42-48 Amps wow !
MSD 6AL2 7 Amps
Aeromotive A1000 in tank fuel pump 13 Amps
lighting 20 Amps
Classic Air unit 25 Amps ?
wipers 4 amps

Looks like roughly a 117 Amp max load or so

Question is , what alternator are you guys using for a similar load , and what mods to the wiring system .
I have already converted over to a volt meter instead of a amp meter.

Who sells an alternator and what brackets will I need to mount it... No GM alternator here ;)
Mancini sells a 120 amp Denso kit , but it says frame mods may be needed for A bodies . I'm thinking I may need a larger one .
What mods are needed for the wiring and does someone have sell a nice front harness for this . I plan on using relays for head lights , cooling fans and the AC unit.
Oh , and the battery will be mounted in the trunk.

Thanks guys !!!

 

[mopardude318]

saw these guys at the spring fling. they are fricken awesome. they can build em however you want, internally or externally regulated, one wire or 3 wire.

i want the 3 wire unit. i like having an excitor wire.

http://www.qualitypowerauto.com/catalog.php?item=557

 

[805moparkid]

im sure your on it but you will not be able to run your stock amp gauge as i think it would just blow... also need to run a new hot lead from the alternator to starter relay/battery

 

[67Dart273]

Are you figurin' on doing any drag racing? Trunk mount battery means some attention to race rules. I'm not up on the details, but the battery must either be in an externally vented METAL box, or a plastic box with a metal firewall at the rear seat. You must have a disconnect which shuts all power, including killing the engine.

One way to do this is to use a 4 post (double pole) disconnect. You can use the auxiliary contacts to provide the ground on a "continuous duty" solenoid up front, being triggered by what used to be the dark blue "ignition run" wire. Then pull all your heavy 12V switched stuff off the solenoid, and you can use the "hot" stud on the solenoid, along with the factory starter relay, if you still use it, for other 12V take off points.

Make DAMN sure you have adequate wiring for this alternator. In no case use the factory bulkhead stuff.

I would use nothing SMALLER than a no 6 from the alternator to the battery junction

Did you get the A/C figure from classic, or are you guessing? That seems high, to me.

You have something against Delco? But yet you'll use a Denso??? Someone on here the other day was talking about using a Ford "3G" alternator which is internally regulated.

This is one way to do it, the alternator output ties into the start relay stud, or the "hot" stud on the added "continuous duty" solenoid

 

[FomocoReformed]

That was me talking about the ford 3g units, I plan to use one in my car since I believe I can get one to fit a stock bracket and snipping off a harness connector at the junkyard. They're not hard to wire in and very reliable high output alts, IIRC the lowest output 3g alt puts out 130amps. DO NOT DO NOT DO NOT I REPEAT DO NOT RUN THIS THROUGH A FACTORY BULKHEAD CONNECTOR OR AMMETER, YOU WILL MELT THINGS THAT YOU DON'T WANT TO MELT. You'll also need to run a larger gauge cable off the charge post, last time did this swap it was on a 79 bronco, I used a 2 gauge charge cable with an in-line megafuse of appropriate amperage for the alt I pulled. If I remember correctly hooking up the voltage regulator harness is a matter of one wire to splice into the factory harness.

I plan to make a writeup on how to do this in our cars but for now this might explain the install.
http://fullsizebronco.com/forum/showthread.php?t=25824

I love using these because they're everywhere, I can go to a parts yard, pull three of them, even if only one tests good I've still spent less than it would cost to get a brand new internally regulated high output unit.

 

[rdakota340]

I used a 136AMP off of a 97 ram just wired it up to constant 14 volt regulater it worked great for me,I had to change the pulley to a V belt.

 

[BillGrissom]

Your current values seem way high. I doubt the fuel pump will draw a steady 13A since that would be 150 W. Most electric fuel pumps draw 1-2 A steady. Your fans won't be on all the time. Most of your figures are probably peak currents when starting a motor and such. I have the original round-back alternator on my 65 Newport w/ electic fuel pump, TBI, and electronic ignition and the only time the battery wouldn't stay charged was when I found one of the 3 alternator diodes had failed. I suggest starting w/ your existing alternator and measuring the actual current draw (alternator output + battery draw) to see what you need. Use a clamp-on DC current probe or put a 100 A ammeter in series for each measurement. You may find that the later square-back alternator will suffice. As mentioned, you must bypass your dash ammeter, or use parallel diodes as I did (search post, too high a threshold for most).

 

[DonnieLawson]

I tried to lean on the high side , max amp draw.
I couldn't find a amp rating on the Aeromotive A1000 fuel pump and the Classic air web site called for a 25 amp relay , which means it should be less....But the fans are rated that from the Spals website , max amp when they are running. Which isn't all the time of course.
I would like to keep it Mopar , but I wouldn't want a GM alternator on it.... Just the hard headed anti-GM in me ;) Maybe a Ford or Denso
I would love to see pics of a conversion , which alternator and which brackets to use etc.
The car is still stripped and in the body shop , I plan on getting the electrical system figured out and all the parts here for when the car comes home for assembly and engine installation
In a nut shell , I would rather go slightly over kill than come up short .
The battery will be enclosed or go with a jell type battery which I think is legal for racing . But it's a 95 % street driven car

 

[RedFish]

25 amps for ac operation may be low. I dont know what kind of draw their blower motor creates. but at the same time you need to supply adiquate current to the compumper drive clutch or it will slip and fail prematurely. Remember that clutch will energize and try to match any engine rpm instantly.
Also anytime the a/c is running those radiator fans will be running. Their amp draw will vary with resistance to air flow/CFM. Add a/c condenser and trans cooler to radiator and you can count on being near their peek load.
New vehicles have 100 amp plus available so you can turn every item on at once.
If I had to choose between a 'denso unit off a Honda ( has a fan ), and a late model Chry' unit ( has more holes shot through it that the typical sponge ), give me the denso.
Just my opinion.

 

[green1]

He showed everything ,except current wiring.

 

[DonnieLawson]

LOL , the wiring is a box in the barn....

Donnie