Alternator for a 1971 351 C. I believe the 55 amp is stock.

Pastorpat

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Alternator for a 1971 351 C. I believe the 55 amp is stock. Can you put a 70 amp alternator on? Any advice and part number appreciated. My alternator has a bad bearing.

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rackerm

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Modified 1970 Mach 1 M-Code with a 351C 4v Manual

I believe 45 amps was the standard stock alternator. The stock 45, 55 and 60 amp units all used the same wire harness. The stock 70 amp used a different wire harness. You can get a aftermarket alternators with higher amps that don't require a different harness.

 

Steve73QMach1

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What type of options do you have ? Things like , power windows and rear window defrost are high current draw options that normally dictated a higher amp alternator from the factory. One of my Mach 1 ‘s has those options and it came with a 70 amp alternator. My other Mach 1 doesn’t have those options and it has a 55 amp alternator.

 
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Pastorpat

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To add to all the confusion. I had a 250 I 6. I installed a 351c into the car. I just used the alt from the 6 cyl. So I was just trying to figure out my options.

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Pastorpat

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To add to all the confusion. I had a 250 I 6. I installed a 351c into the car. I just used the alt from the 6 cyl. So I was just trying to figure out my options.

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delawarebill

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[url=https://ibb.co/nRVcVLd][img]https://i.ibb.co/yVMyMQv/side.png[/img][/url]
since u changed engines u are not keeping it numbers correct.. put on a 70a if u want.. when i rebuilt my engine this yr the old alt was not as nice as the engine.. i replaced it with a chrome 100a. driving all summer and not an issue.

 

bkdunha

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Attached are the 71 Alternator specifications across all engines.  The 250 had a stock 38 amp standard and 55 amp with AC

71 Alternator AMA Specs.docx

 

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boilermaster

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To add to all the confusion.  I had a 250 I 6.  I installed a 351c into the car.  I just used the alt from the 6 cyl.    So I was just trying to figure out my options.  

Pastorpat,

you might want to consider changing over to a one wire internal regulated alternator.

Summit racing has delco remy style alternators that have been converted for our cars (cases re worked for spacing )

They have 100A (81038 ) and 140a 810300, wiring is a snap and probably no one will ever know you have a gm alternator on your mustang.

mine has worked great for the last year.

The stock alternators that came on our cars were not all that great, and even 50 amps is not near enough if you are running lots of accessories.

Boilermaster
 
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