what amperage alternator?

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1969moparDART

1969moparDART

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The title says it all i just need to know what amperage alt i should buy for my 1972 318
 
Generally the stockish 60-65 amp is fine as long as you are not adding a big stereo amp or other high load electrics.
There are 2 types also in case you didn't know.
There is the roundback and squareback style, and of the two the squareback is best because it puts out more at idle than the roundback.
Our 72 has the squareback which can be identified by it's square area for the Diodes, and a two wire field. (three total wires connected to it)

Also, since the AC cars generally used two belts the alternators usually come with a double belt pulley on them because they can be used for AC and non AC (1 or 2 belt)cars both.
This way they don't have to carry both.
The single pulley can be removed from a single and installed in place of a double though.
 
TrailBeast said:
Generally the stockish 60-65 amp is fine as long as you are not adding a big stereo amp or other high load electrics.
There are 2 types also in case you didn't know.
There is the roundback and squareback style, and of the two the squareback is best because it puts out more at idle than the roundback.
Our 72 has the squareback which can be identified by it's square area for the Diodes, and a two wire field. (three total wires connected to it)

Also, since the AC cars generally used two belts the alternators usually come with a double belt pulley on them because they can be used for AC and non AC (1 or 2 belt)cars both.
This way they don't have to carry both.
The single pulley can be removed from a single and installed in place of a double though.
Click to expand...
awesome thanks man, so would a 95 amp be ok because i do have an aftermarket radio and 2 8inch speakers?
Powermaster 17519: Upgrade Alternator Chrome Finish | JEGS
thats what im looking at
 
1969moparDART said:
awesome thanks man, so would a 95 amp be ok because i do have an aftermarket radio and 2 8inch speakers?
Powermaster 17519: Upgrade Alternator Chrome Finish | JEGS
thats what im looking at
Click to expand...

That alternator will/should only put out what the car needs to run things and keep the battery charged, so a 95 won't make any difference as in being too big for it.
One thing that is possible for example, the old wiring in these cars may not be up to carrying the load if the alternator goes high in it's output for some reason.
Like a large charge load from a real low or dead battery. (or giving someone a jump)

It's not a huge deal, but you need to know it's possible.
But then again a 60-65 amp will easily toast things too under those conditions.
One major weak point is a plastic connector by the passenger side head where the OE engine harness connects on some of these cars, but this should be noted with any alternator.
 
TrailBeast said:
That alternator will/should only put out what the car needs to run things and keep the battery charged, so a 95 won't make any difference as in being too big for it.
One thing that is possible for example, the old wiring in these cars may not be up to carrying the load if the alternator goes high in it's output for some reason.
Like a large charge load from a real low or dead battery. (or giving someone a jump)

It's not a huge deal, but you need to know it's possible.
But then again a 60-65 amp will easily toast things too under those conditions.
One major weak point is a plastic connector by the passenger side head where the OE engine harness connects on some of these cars, but this should be noted with any alternator.
Click to expand...
ok cool, and is that the round or square back?
 
1969moparDART said:
ok cool, and is that the round or square back?
Click to expand...
Not sure what part you are asking about, but the squareback is the better/newer one.
The squareback can be installed where a roundback was with a little mod to the wiring.
 
TrailBeast said:
Not sure what part you are asking about, but the squareback is the better/newer one.
The squareback can be installed where a roundback was with a little mod to the wiring.
Click to expand...
im sorry, my question was in relation to the alt i posted
 
1969moparDART said:
im sorry, my question was in relation to the alt i posted
Click to expand...

Ah, ok.
The one you posted the link for is a squareback. (you can tell by the big square area on the back of it)
If you used to have a roundback we can tell you how to wire for this new one.
It's not a big deal at all.
 
TrailBeast said:
Ah, ok.
The one you posted the link for is a squareback. (you can tell by the big square area on the back of it)
If you used to have a roundback we can tell you how to wire for this new one.
It's not a big deal at all.
Click to expand...
ok i thought it was and the old one is a square back as well so it will bolt right up thanks for the help man.
 
Disagree, Greg. THERE IS NO WAY I'd put bigger than about a 50A on "stock" factory wiring. OP..........Please read the MAD article. Even if you do not do this mod, it lays out the whut, whyies and "stuff happens" about the factory wiring.........

All you need is to park the car awhile, the battery gets down, and whatever "big" alternator you have will REALLY be pumping out the stuff until the battery comes back up.

Catalog

Even "Ma" knew this back in the day. When you bought an optional 65A alternator, "Ma" implemented so called "fleet wiring." Look it up, it's documented in some of the shop manuals, not always A bodies, but at the least for B/ C bodies. This was in effect a bypass for the bulkhead connector
 
67Dart273 said:
Disagree, Greg. THERE IS NO WAY I'd put bigger than about a 50A on "stock" factory wiring. OP..........Please read the MAD article. Even if you do not do this mod, it lays out the whut, whyies and "stuff happens" about the factory wiring.........

All you need is to park the car awhile, the battery gets down, and whatever "big" alternator you have will REALLY be pumping out the stuff until the battery comes back up.

Catalog

Even "Ma" knew this back in the day. When you bought an optional 65A alternator, "Ma" implemented so called "fleet wiring." Look it up, it's documented in some of the shop manuals, not always A bodies, but at the least for B/ C bodies. This was in effect a bypass for the bulkhead connector
Click to expand...

That is exactly why I added the disclaimer about possible high output instances where it could be a problem.
But a lot of people do it anyway.
 
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