GM Alternator Swap

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GM Alternator Swap

Post by revbang1 » Wed May 16, 2018 12:46 pm

I was very pleased to find and read the helpful info on the GM alternator alternative for my 67 1600 Roadster. I hope to do it tomorrow. I had two questions:
1) Will my amp meter in my dash still work after the GM swap? I was a bit confused about the voltage meter option mentioned at the end of the article.
2) There was also the mention of a 16 gauge fuseable link in the second to last section of the article. It wasn't mentioned in the parts that are needed to be purchased.

If someone could explain my above concerns, I would be grateful. My Roadster has been off the road for almost 10 years. I am getting really close to driving her again. Thanks in advance.

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Re: GM Alternator Swap

Post by Toptech360 » Wed May 16, 2018 9:10 pm

I can't help with question 1 but question 2 I can. The fusable link is usually installed from between 3" to 12" from alternator post. An inline fuse can also be used and is easier to replace if it pops. It's a safety measure to protect from harness catching fire if there were a short to ground or the regulator fails and starts overcharging.

Read up on the denso alternator thread for some more advice on fuse protection
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Re: GM Alternator Swap

Post by ct06033 » Thu May 17, 2018 2:22 am

I have the GM swap on my 68. The amp meter works just fine if you use the original circuit. There is a danger of burning up your wires and or amp meter however, which is where the fuse comes in.

So you would put a new positive wire on the alternator with an inline 30-40amp fuse, and splice that to the original positive wire (that would go on the positive stud on the original alternator) and you need to bridge the sensor wire to the positive stud as well. at this point, the connector (4 wires on a 68) and external regulator are useless. you can take them out or leave them in for looks (like i did) but the rest of the circuit will work as normal including the amp meter. At this point you can call it good or switch to a volt meter, but its not necessary.
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Re: GM Alternator Swap

Post by ppeters914 » Thu May 17, 2018 2:57 pm

Here's a pic (click image to get larger view).
  • Fuse is mounted where external voltage regulator used to mount.
  • One wire is connected to the heavy white wire that goes to the ammeter. The shorter one goes to the BAT post on the alternator.
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Re: GM Alternator Swap

Post by Curtis » Thu May 17, 2018 7:21 pm

If you use a screw post circuit breaker there is no need to butcher your stock wire. ... gKtAvD_BwE
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