1973 Fastback (71 351C) - I need help hooking up alternator!!!

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perryseth

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Well, I feel like a turd because I have recently rebuilt my 351 Cleveland and yet I can’t figure out how to properly hook up the alternator. To provide some background, I rebuilt the Cleveland back in 2003 with the help of a friend who let me use his heads and a tremendous amount of work was done to the engine and I’m guessing it makes about 400 hp. I do recall putting in a “GM alternator” with his help.The alternator is a AutoZone Dura last 7078. I have one red wire with a fusible link going from the battery post on the alternator to the battery side of the starter solenoid because I thought that’s how it was hooked up.  Thinking I had a bad alternator I went to Autozone yesterday and they were too busy to test it so I asked them to just replace and they did.They put I put the alternator on last night and started it up and it still not showing with a voltmeter at the battery that it is charging because the voltage is the same as when the car is off. I did make sure to have the RPMs over 2000. Now that I’m reading it looks like this particular alternator is externally regulated but I don’t have a voltage regulator at all hooked up to this mustang.  I thought that when the alternator was spinning it sent electricity out through the red wire that would then charge the battery at the same time but I’m thinking that shows how little I truly know about the cars electronica system.

I look forward to contributing to other peoples questions that I have learned quite a bit through the process. The engine and transmission and rear end or out of a 71 Mustang that I had sitting in theGarage from age 5 until someone helped me build it when I was 16 back in 1996.  

I usually steer clear of forums like this because there seems to be a lot of grumpy people who pass their time by trying to make the posters feel stupid. I don’t want any smart ass replies just give it to me straight and I will answer any question the best I can and send any pictures or video needed to help resolve this issue. 
thank you much!

perryseth

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cv_72mustang

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Hi ,  Never really find gumpy folks here.   I belive you are going to need an external regulator.  Here is link of  block diagram.  It might help.   Folks on this site will provide more detail.  




 
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cv_72mustang

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Don C

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Yes, you are correct, that alternator is a stock style and will require an external regulator. The wiring diagrams referenced in the first 2 answers will show you how to wire it. Hopefully the light green with red stripe wire is still someplace under the hood, it comes from the ignition switch or alternator warning light, depending on if you have gauges or idiot lights. The rest of the wiring is fairly straight forward. The easiest, although not fastest, solution will be to get a new alternator harness. You'll need to make sure you get the correct harness, that matches alternator size and with or without gauges:

1965-1973 Mustang Restoration Alternator Feed Wire Harness - National Parts Depot (npdlink.com)

 

cv_72mustang

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Just to add. I purchased the retro harness (non-guage)  kit Don mentioned this summer and it worked out well.  Just recheck the schematics because the new harness has different colored wires and boot covers on some of the connections. 

 
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Don C

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By the way, the only time you're likely to get any negative feedback on this forum is to mention installing GM parts on your Mustang, especially something like a wart hog butt-ugly HEI distributor. And if you really want to create an uproar mentioning installing an LS engine in your fastback will do it  :biggrin:

If you decide to go back to a one wire alternator, there are better choices than a stock GM. The Ford 3G alternators are a good choice, although they require two wires. An economical 63 amp one-wire is available from DB Electrical, they also have higher output one-wire GM alternators (GM one-wire alternators is probably the one exception to the GM grumpy rule).

Alternator 1 Wire Universal Self-Excited 10SI 10 SI 7127-SE - DB Electrical

High Output Chevy One 1 Wire Alternator 105 Amp 10Si-Se - DB Electrical

We hope you enjoy this forum, you'll get plenty of help here, and opinions.

 
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perryseth

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Thank you guys so much!!  I’ll post the solution when I get the work completed.

 

perryseth

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I got the DB Electrical universal alternator and it works like a champ!!  I paid a couple of extra dollars ordering it through Amazon prime, but I got it in two days and I really like returning their stuff at Kohl’s because it saves a lot of time.  
 

One wire right to the starter solenoid!  I had to bore out the top hole in the alternator body so the long bolt would fit, and I had to add in a piece of a spacer as well.  It’s a little bit off alignment so I’ll fix it later.  Also- the adjustment bolt was a different size so I used an older bolt I had that fit.  Ty again for the help

 
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