Alternator upgrade - which one?

[tommyg29]

I know this has been asked before, but I have a couple specific questions I havent seen in the search.
I think I have a stock type alternator, and I run an electric fuel pump, vintage air, power windows and a radio. Nothing much else should put an unusual drain on the battery. I think the headlights are stock wired, as are the front fogs or running lights whatever theyre called. I think a "minor" upgrade to about 75 amps should be enough, which leads to my first question: with an upgrade to about 75 amps will I need to upgrade the other wiring such as the bulkhead connector?
Second, will any upgrade render my amp gauge in the dash inaccurate or unusable?
Finally, what upgrade alternator would you suggest to make the easiest swap? I've seen several types suggested such as the smaller ND and the later version mopars. I know the wire to the starter relay should also be upgraded. The gauge looks ridiculously small compared to modern cars.
Thanks.

[the_engineers]

Not sure about the 75A...here's a link for doing a 90A.
http://goodysgotacuda.com/DensoUpgrade.html

[tommyg29]

Ive seen that. I printed out the srticle and the M.A.D. article also which describes the issues with the amp gauge system. Lots of reading material for the next few days, but I definitely want to avoid losing my amp gauge. Prior owner spent $$$$$ restoring the gauges, clock, etc, and I love the stock look/functionality. Also hoping to avoid a major project with a "minor" upgrade, but things are what they are.
With my electrical issues, I just think the stock alternator is stretched past its limit.

[the_engineers]

Do you think a later 65A would work?  Probably would require minimal changes.

[matt63]

I just went with a Nippo 130 amp unit off of a newer truck.  I think I was looking for a  physically smaller unit.  IIRC I did refer to the above link for the upgrade.  Remember, do not run the extra current through the bulkhead connector as it was not designed for this. You must run another wire from the alternator to a terminal that feeds the fuel pump, fans, etc.

[tommyg29]

Quoting Chryco from a similar thread: "add a jumper from the Alt ouput to the power stud on the start relay to take some of the load off the ammeter & bulkhead connections".
I assume this is what you mean also.
So in summary, if I do this, and maybe add the headlight relays I've read about (more research), an upgrade to 75 or 90 amps might not stress the bulkhead connector or the amp gauge, and the gauge will still work, but not accurately?
Is that about right?
Here are some pics of my setup:
Thanks.

[BruteForce]

That's about right. But I notice in the picture you're using crimp-on terminals. If you do that for the new primary wire, and over time the crimp-on degrades, it'll shift more and more of the load back into the old primary circuit which will then burn.

For the primary wires, use crimp and solder connections. To do this:

1. use a utility knife to cut off the yellow plastic insulator
2. slip heat shrink tubing over the wire
3. crimp the terminal on the wire in the usual manner
4. solder the connection
5. pull the heat shrink tubing over the connection and shrink it on

For a better solution, what I did was add a fusible link and route both the old primary bulkhead wires to the starter relay: http://www.madelectrical.com/electricaltech/amp-gauges.shtml

Your ammeter will no longer register anything, but at least it's a much more robust circuit.

[dodj]

For the primary wires, use crimp and solder connections. To do this:

1. use a utility knife to cut off the yellow plastic insulator
2. slip heat shrink tubing over the wire
3. crimp the terminal on the wire in the usual manner
4. solder the connection
5. pull the heat shrink tubing over the connection and shrink it on


Your ammeter will no longer register anything, but at least it's a much more robust circuit.

In an effort to make them as waterproof as possible I did the same as you suggest, but also put RTV in the heat shrink. I made new wiring harnesses for my Challenger in 1986 and so far no problems using the method described by BruteForce.

Even though the ammeter doesn't register, to the casual observer everything looks good.

[tommyg29]

I have read LOTS of the electrical how-to's. Probably printed out and read 30-40 pages so far. The headlight relays seem like a no brainer, but I just cant stand disabling the amp gauge. I'm holding out hope theres gotta be a way to take some of the load off the bulkhead connector and the gauge without doing that. I've gotta mull this one over.
Also, my alternator seems to have a band in the center which makes it thicker than the ones I see in the how-to's. Can anyone tell from the looks of it what type, output it has? It could already have been upgraded. Can I tell from the numbers on the back, though they're hard to make out, being mostly covered.

[ntstlgl1970]

The highest output stock parts store square back (2 field terminal) alternator is a 65A. The ND late model alternator is the easiest swap, make sure to do the harness upgrades like everyone has mentioned. The ammeter isn't going to indicate anything useful after swapping. I'd rather have a non-functioning but good looking ammeter than a burned up engine or dash harness.

[71 DEPUTY]

what I did for the deputy was to get the old 65amp redone to a 75 amp unit- increased the wires size by two- ran it thru a hole in the firewall via a rubber grommet to the amp meter- making sure that the amp meter studs where tight and used tooth washers to bite into the eyelets, then using the same size wire back thru the same grommet to a larger fusable link to the starter relay.  I left the existing two wires that where on the amp meter studs to feed the existing cars wiring and removed the wires from the engine side bulkhead harness!!

no problems for 7 years and the amp meter works great- also do the headlight upgrade- its worth it!!!!

[tommyg29]

what I did for the deputy was to get the old 65amp redone to a 75 amp unit- increased the wires size by two- ran it thru a hole in the firewall via a rubber grommet to the amp meter- making sure that the amp meter studs where tight and used tooth washers to bite into the eyelets, then using the same size wire back thru the same grommet to a larger fusable link to the starter relay.  I left the existing two wires that where on the amp meter studs to feed the existing cars wiring and removed the wires from the engine side bulkhead harness!!

no problems for 7 years and the amp meter works great- also do the headlight upgrade- its worth it!!!!

Now here ya go!
This will solve the bulkhead connection issue, and save my amp gauge, though still keep some potential risk at that point, but at least I can minimize it. And yes, I'm sure I can have my existing alternator rebuilt/rewound to produce a few more amps.
Can I install relays for my fuel pump also?

[dodj]

Now here ya go!
This will solve the bulkhead connection issue, and save my amp gauge, though still keep some potential risk at that point, but at least I can minimize it. And yes, I'm sure I can have my existing alternator rebuilt/rewound to produce a few more amps.
Can I install relays for my fuel pump also?

Like you say, it gets rid of 50% of the risk. Keep an eye on the ammeter connections, make sure they are tight and clean (as Deputy says).
You can install relays for just about anything you want, just make sure the relay you buy can handle the expected load (amps).

[BruteForce]

I put my electric fuel pump on a relay. It wasn't really necessary, as it only draws 3 amps, but what the heck!

[duodec]

I put my electric fuel pump on a relay. It wasn't really necessary, as it only draws 3 amps, but what the heck!

Since you used one anyway, with the right relay you could install a sneaky cut-off switch to keep the pump from running...