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**dmjlambert** · 05-04-2018, 07:18 PM

I only have opinions and take it with a grain of salt because I am not as experienced as VetteVet and many others on the forum. I have stock options, with mechanical fan and fuel pump, so I also don't have the same situation as you. With that said, these are my 2 cents worth of opinions. :-)

That forum post "Internal Alternator Wiring" for me was not very good. I was confused after reading it. I think you need resistor or diode or perhaps both. It is not clear to me. There's some more resistance or bigger resistor needed in the wires to protect the CS style alternator internal circuitry.

After reading all the information about alternator swaps, for me the clear choice was 12SI, because all I had to do is buy the alternator and buy the conversion adapters. One adapter you plug in in place of the external regulator. I didn't even remove my old regulator, it is still on the radiator support sitting there unhooked. The other adapter plugs in the 12SI alternator and provides a place to plug in the stock wiring harness. The bolts fit. The v-belt fits. Done.

The video. The guy is using some alternator of unknown part number from a junk car, and looks like he was partially through the process of installing and backed up to make the video with wires already cut off. It is hooked up in a hokey manner, with the clamp type emergency repair terminal on the battery. He uses wire nuts, does not use a fusible link, and specifically mentions that ground is not really important. He bent his alternator bracket and flipped it over to make it fit. He has an idiot light dash, so his application is different. If the objective is to get going with bubble gum and baling wire approach, I guess it is OK, but for me the whole procedure was alarming and I don't care for it. It'll work just fine, all you have to do is fix it when it doesn't work.

So, if it were my truck with the electric fans and fuel pump and other wizbang modern stuff, I would get a 12SI alternator and conversion adapters and hook it up. Change the clocking if necessary. I have not changed the clocking on mine, but it seems simple. Here is a video. https://www.youtube.com/watch?v=91lfKtbU7ew Mad Electric website mentions you should use an impact wrench and gloves when removing the pully. I believe them. I would get some 10 gauge red and black wires and terminal rings from Autozone, solder the terminal rings on the wires, and connect them directly to the alternator output and alternator ground in addition to the stock wiring connections, and run those additional 10 gauge wires directly to the fan relays and fan ground, so there is a really good connection. I think the fans are the big power sucker on your truck and everything else would run fine off of the stock wiring. If you want the ammeter to operate normally, run all accessories from wires attached at the alternator or fuse block in the cab instead of at the battery. Hooking up at the battery is not an "issue" except it will mess with your ammeter.

From Mad Electrical
"12SI, 94 amp, at 3:00 (AC-DELCO # 321-266, Lester #7294-3)
Tell the auto parts counter person that The alternator is for a 1984 High performance Chevy Camaro, with 5.0L (305G) engine, 94amp alternator"
that would probably be my choice. 3:00 looks like it would keep the wires away from your engine. If you had to re-clock it, that job does not look too scary.

05-04-2018, 07:18 PM	#12
dmjlambert Senior Member Join Date: Apr 2016 Location: Cypress, TX Posts: 3,561	Re: Alternator question I only have opinions and take it with a grain of salt because I am not as experienced as VetteVet and many others on the forum. I have stock options, with mechanical fan and fuel pump, so I also don't have the same situation as you. With that said, these are my 2 cents worth of opinions. :-) That forum post "Internal Alternator Wiring" for me was not very good. I was confused after reading it. I think you need resistor or diode or perhaps both. It is not clear to me. There's some more resistance or bigger resistor needed in the wires to protect the CS style alternator internal circuitry. After reading all the information about alternator swaps, for me the clear choice was 12SI, because all I had to do is buy the alternator and buy the conversion adapters. One adapter you plug in in place of the external regulator. I didn't even remove my old regulator, it is still on the radiator support sitting there unhooked. The other adapter plugs in the 12SI alternator and provides a place to plug in the stock wiring harness. The bolts fit. The v-belt fits. Done. The video. The guy is using some alternator of unknown part number from a junk car, and looks like he was partially through the process of installing and backed up to make the video with wires already cut off. It is hooked up in a hokey manner, with the clamp type emergency repair terminal on the battery. He uses wire nuts, does not use a fusible link, and specifically mentions that ground is not really important. He bent his alternator bracket and flipped it over to make it fit. He has an idiot light dash, so his application is different. If the objective is to get going with bubble gum and baling wire approach, I guess it is OK, but for me the whole procedure was alarming and I don't care for it. It'll work just fine, all you have to do is fix it when it doesn't work. So, if it were my truck with the electric fans and fuel pump and other wizbang modern stuff, I would get a 12SI alternator and conversion adapters and hook it up. Change the clocking if necessary. I have not changed the clocking on mine, but it seems simple. Here is a video. https://www.youtube.com/watch?v=91lfKtbU7ew Mad Electric website mentions you should use an impact wrench and gloves when removing the pully. I believe them. I would get some 10 gauge red and black wires and terminal rings from Autozone, solder the terminal rings on the wires, and connect them directly to the alternator output and alternator ground in addition to the stock wiring connections, and run those additional 10 gauge wires directly to the fan relays and fan ground, so there is a really good connection. I think the fans are the big power sucker on your truck and everything else would run fine off of the stock wiring. If you want the ammeter to operate normally, run all accessories from wires attached at the alternator or fuse block in the cab instead of at the battery. Hooking up at the battery is not an "issue" except it will mess with your ammeter. From Mad Electrical "12SI, 94 amp, at 3:00 (AC-DELCO # 321-266, Lester #7294-3) Tell the auto parts counter person that The alternator is for a 1984 High performance Chevy Camaro, with 5.0L (305G) engine, 94amp alternator" that would probably be my choice. 3:00 looks like it would keep the wires away from your engine. If you had to re-clock it, that job does not look too scary. Last edited by dmjlambert; 05-04-2018 at 08:18 PM.