Alternator choice

[6t727t2]

Will be replacing original external reg alt with internal reg alt in a '72 Cheyenne 402/400 a/c. Any Chevy year specific better than any other year? Thanks

[Rich72C10]

interested in this...

[ChevyRacefan]

I used a 1985 pontiac trans am 96amp unit, it is clocked the correct way, just make sure you get the v belt pulley , or swap yours on it.

[gmc684x4]

The 73 to 87 10 and 12si alternator are better then 67 72 alternator

Cs130 and 144 are better then the 10/12si alternator

There is some cs130 alternator that will fit the older style brackets
I never looked into them since my donor vortec brackets came with a new cs144 alternator

[ChevyRacefan]

Originally Posted by gmc684x4

The 73 to 87 10 and 12si alternator are better then 67 72 alternator

Cs130 and 144 are better then the 10/12si alternator

There is some cs130 alternator that will fit the older style brackets
I never looked into them since my donor vortec brackets came with a new cs144 alternator

The cs130 & 144 are better, but also can produce a lot more amps, I would upgrade the alt to battery wire when using them.
The gauge wire in the trucks designed around 43-68 amp alts. isn't up to the higher amp output of the cs130 & 144

[gmc684x4]

43 amp alt main battery wire is not up to 12 si 100 amp output either

Op asked about alternator upgrade styles

Output wire needs are also part of how many amps will you truly need I will be running a 15000 lbs warning winch so even at 140 amps may be a little small and big alternator wire to battery will need to be sized for over 140 amps

[ChevyRacefan]

Originally Posted by gmc684x4

43 amp alt main battery wire is not up to 12 si 100 amp output either

I never said it was.

[Stocker]

I had electrical problems a few years ago and ended up replacing my alternator, also did some minor wiring upgrades to handle the additional amperage. I was totally over my head and never could have done it without some great help from other board members. Ended up with a 94 amp alternator for a 1985 Buick Riviera, and it works perfectly. Link to the thread with all the details: http://67-72chevytrucks.com/vboard/s...d.php?t=772236

['68OrangeSunshine]

For my '71 GMC Jimmy w/350, I oredered an alternator [10 SI] for a '77 Blazer w/350.
Then you only have to splice in leads for the back of the Delcotron, and jump F to 3, and 1 to 2, at the EVR plug.

[HO455]

It is not just a model year choice, but a choice of needed amperage and which late model system to achieve the output desired.
Here are links to the Mad Electrical site. There is a lot to read and certainly worth the time in order to make the decision that will be best for you.

http://www.madelectrical.com/electri...hreewire.shtml

http://www.madelectrical.com/electrical-tech.shtml

And if your interested here is link to how I converted to a late model SC130 alternator and the appropriate wiring changes. Scroll to post 467.

http://67-72chevytrucks.com/vboard/s...698377&page=19

[MARKDTN]

The 10si and 12si are basically bolt on and minor wiring changes. Don't think it matters what year, and they are all pretty easily re-clocked. 12si has improved cooling so they are better but really any SI series alternator is OK.

I would not use a CS130 for a paperweight. They got better over time, but the reliability was awful.

CS144 is a good unit. The '93-'96 5.7 Roadmaster/Caprice is a good application that is clocked correctly and has usable ears. I have one of these on my '83 K20. I am using long water pump and a modified upper bracket. I am using '80s Monte Carlo pullies on crank and water pump so I get a serpentine style alternator belt (not quite as wide as the Roadmaster, but works fine) and a/c and steering pump remain V-belt style. Delco makes a plug to put a CS130 or CS144 in place of an SI style alternator. You could use it on an external regulator style, but would require some re-wiring first.

Non-resistor adapter(dash light): AC Delco: 8077
Resistor adapter(dash gauge): AC Delco: 8078

After re-reading the posts above I felt compelled to agree on upgrading the wire from alternator to Battery. On my CS144 upgrade, I added an additional 8ga wire from alternator post to battery to be sure that the stock wiring was not overloaded. That is overkill, but better to be safe. You could also go to the starter lug with it, but the battery is closer. I have electric fans (which is why I upgraded in the first place) and they pull power from the same spot. Big alternators do not play nice with factory ammeters so if you have one, you will probably have to either bypass it or change to a voltmeter.

[Grumpy old man]

I used this 10SI 105amp one wire . stock brackets .

https://www.ebay.com/itm/New-Alterna...4/142407861646

https://www.google.com/search?q=inst...sXs_QbYnY6YAg7

[DeadheadNM]

Originally Posted by 6t727t2

Will be replacing original external reg alt with internal reg alt in a '72 Cheyenne 402/400 a/c. Any Chevy year specific better than any other year? Thanks

Harry here’s a bolt on setup I’ve stuck with: http://67-72chevytrucks.com/vboard/s...1&postcount=15

And here’s an example of the adapter harness that’s plug and play. Clean. https://www.ecklers.com/full-size-ch...All%20Products

[bry593]

I used a 78 amp, 12-SI from an '85 Caprice. There is no need to go crazy on the amps, especially if you are using the factory 12 gauge charge wire to the battery. I changed my charge wire to 10 AWG, GXL and replaced the factory fusible link with a 30amp midi fuse.

On a side note, I also removed the factory amp gauge and replaced it with a square body volt meter.

['68OrangeSunshine]

Originally Posted by HO455

It is not just a model year choice, but a choice of needed amperage and which late model system to achieve the output desired.
Here are links to the Mad Electrical site. There is a lot to read and certainly worth the time in order to make the decision that will be best for you.

http://www.madelectrical.com/electri...hreewire.shtml

http://www.madelectrical.com/electrical-tech.shtml

And if your interested here is link to how I converted to a late model SC130 alternator and the appropriate wiring changes. Scroll to post 467.

http://67-72chevytrucks.com/vboard/s...698377&page=19

I made sure my '' '77'' Alt was 63A so I wouldn't have to change any existing witing. [Outside of the EVR].

[dave`12]

Check this out.

All the info you could ever ask for is here.

http://www.67-72chevytrucks.com/vboa...d.php?t=763180

[garyd1961]

I'm not sure what mine is, think it came out of a 87 S10. I had 3 or 4 good alternators laying around and picked the one I liked best and wired it up.

[Andy4639]

Nothing has to be done except a few simple wires cut and reconnected. You can buy the pigtails if you like are just use crimp connections and call it done. Personal preference is all it is here.

95 Buick Riviera 94 amp alternator:

If you want a clean install:
Disconnect all the wires from the old alternator and remove. Install the new alternator. Ground it. Put the Red heavy 12R gage wire back on the nut terminal like on the old alternator.
Now you are ready to strip the harness back.
Take the wire connector off the voltage regulator and cut the Brown & Red wires off of it. Unwrap the harness from the VR back to where the Black & Blue wire run over to the alternator. Once you have the harness unwrapped you can throw the VR and Blue & Black wires away you want need them.
Run the brown wire straight to the alternator to the #1 terminal. Use a female spade on the end of it and install.
Then the red wire that went to the VR now goes straight to the alternator #2 terminal. Do the same with it. Female spade connector and install. (optional is you buy the pig tail)
(Note) Don't short cut the red wire. They both need to run from the junction to the alternator. Don't jumper them.
The Blue & Black wires are thrown away and not used.
Then take the old external voltage regulator out of the truck and toss it!
That's it nothing has changed in the wiring harness except 2 less wires and the truck will run better for it.

This is the simplest way to do this and when done you don't have a glob of wires taped up. Less chances of a short and looks factory.

[Rich72C10]

Where is the junction actually at?

I have a '72 C10 where the horn relay is under the dash, near the column. When I talked with the M.A.D. guy today (mark) he suggests moving the junction to the firewall (near where the firewall connection to the dash passthrough is at).

[Andy4639]

Originally Posted by Rich72C10

This is the junction actually at?

I have a '72 C10 where the horn relay is under the dash, near the column. When I talked with the M.A.D. guy today (mark) he suggests moving the junction to the firewall (near where the firewall connection to the dash passthrough is at).

Its in the bundle of wire by the old VR in the wiring harness. Its just a solder joint. There is also one inside the truck under the dash. The pictures are of the one I redid in the 68 step side truck and I cut the wires and added the junction block so I could add to it if needed.

[Rich72C10]

Thanks Andy... on M.A.D's site it talks about newer than 1971's but with the horn relay being under my dash (not near the regulator or mounted on the firewall) I was getting confused where the "splice" was actually at in my truck.

It seems he has a real nice kit(s). I could have gotten things cheaper but the supplies are suppose to be top notch for power rating and holding up in the hot engine bay.

[Fbks_Cruiser]

When I upgraded to a 12SI alternator using the upper diagram in Andy’s post, I replaced that soldered junction with a buss bar. It also gave me a place to grab power when I installed headlight relays. ( you can see them in the bottom of the picture.

[Rich72C10]

Matt, that is really clean looking!

The kit that I am getting from Matt @ M.A.D. will have a junction like the attached photo. Per my chat with him, I'll put it up on the firewall and moving the OEM Splice up there.

He was not too happy where I placed my headlight relay harness that I got from LMC (that little junction near the battery on the passenger fender). So I have to give that some thought now. I can't remember why he wasn't happy about it though (it was a 1 hour convo going all the way back to Model A Generators!).

[Fbks_Cruiser]

Yeah. I talked to him as well before changing over my alternator. Good guy with a wealth of information and happy to share his knowledge. I think he may have not wanted you to grab power for your headlights at the junction near the battery because it will adversely affect your ammeter if you are still running one with the shunt system as in the diagram (that’s what the 18g black and black/white wires are for). Vett can correct me if I’m wrong on that. It is the reason I didn’t increase the wire size between there and my buss bar. It would have changed the resistance to which the ammeter shunt is sensitive.

[Rich72C10]

Ah, that is it! Which I do have gauges (not just a warning light).

That brings up a worry, if I move my junction up to the firewall - how do I keep the gauge reading correctly? It seems he talked about the OEM gauge not being all that good of telling you anything - showing charge vs voltage?? Not that I want to figure out how to flip my OEM dash gauge at all (non-starter for me).

After all this reading here and on the M.A.D. site - it seems to be a bit of a balancing act on the power/charging routes. Seems like I could really mess this part up, just by trying to supply more/beefier power to goodies.