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1948 - 1956 F1, F100 & Larger F-Series Trucks Discuss the Fat Fendered and Classic Ford Trucks

generator-alternator

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Old Feb 24, 2026 | 12:16 PM
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generator-alternator

I'm installing a Generator-alternator, ( an alternator that looks like an original generator), in my 56 f100 because I have a HEI ignition and I'm hopping to improve the performance. I've read that a volt gauge is recommended over an amp gauge due to the high output of the alternator heating up the wiring. Shall I disconnect the amp gauge and install the volt gauge or run both. Is there a risk of fire with the amp gauge connected? Thanks in advance for any input.
Rick
 
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Old Feb 24, 2026 | 12:46 PM
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Well, lets look at the specifications for some answers:

What is the rating of your generator?

What is the rating of your new alternator?

What is the range of your amp gauge?
 
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Old Feb 24, 2026 | 04:23 PM
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Not sure if this is the rating. The amp gauge goes to 60 amps
This came with the alternator.
This came with the alternator.
 
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Old Feb 24, 2026 | 04:25 PM
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Not sure what the generator rating is
 
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Old Feb 24, 2026 | 04:50 PM
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Just giving a quick look over things here, the largest generator in the Ford book was 60 amps, and that seems to match your amp meter range. The 82101-2 alternator you show is rated for 90 amps. As such, the gauge cannot reflect the full range of the alternator. This may or may not have longer term consequences for the amp gauge if consistently pegged out of range.
 
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Old Feb 24, 2026 | 05:59 PM
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So, if never peg my present amp meter the wiring won't overheat?
 
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Old Feb 24, 2026 | 06:01 PM
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So, if never peg my present amp meter the wiring won't overheat? Am I reading it, at idle the amps are at 68?
 
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Old Feb 24, 2026 | 06:13 PM
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The charts will tell you that 60 amps vs 90 amps at 12V may require heavier wire.
 
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Old Feb 25, 2026 | 12:21 AM
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Thank you for your help sir.
 
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