Buttersvette

I have a 1968 stock 327 with fuel injection and a/c. It is time for a new alternator. I have stock set up with external regulator and would like to go to internal style. I know there is the by pass wire kit but trying to figure out what amp alternator is good for F/I and a/c. I don’t want to change my gauge or other wires if possible.(other posts have suggested that) I also don’t want to change brackets, belts etc. Any thoughts? Any help would be greatly appreciated!

resdoggie

My a/c equipped car with options such as pw and rr widow defogger, has a factory 63A alt. I'm thinking FI is not an issue because it's not a big power consumer. No wiring issues. That said, I would go with an 80-100 amp just in case you want to switch to electric fans at a later date or install a 1000w sound system.

carriljc

I have EFI, electric fuel pump, Lincoln Mark-8 fan, and a/c on my 68. I recommend converting to a 140 amp CS-144. I first converted it to 94-amp 12Si and that worked well, but when that wore out I went and bought a CS-144 at the junkyard just to see if it fit (20 bucks so what the heck?). Fit fine so I got a 12si to cs-144 adapter lead and wired it all up. Terminal voltage is maintained noticably better with the CS-144. I would just jump to CS-144 instead of going through the intermediate steps. If you want more info just ask. It's going to cost you about the same anyway, so just go BIG... it's all around better.

Buttersvette

Thank you for your response. I have all new wiring (stock) and I forgot about the power windows. I do not want to burn this car up so I am hoping you can answer a few questions. I live in a little town with a few auto parts stores. Most works have no idea how to look up a part if it doesn't say so on their computer. Can I go in and ask for a cs-144 alternator or do I have for a specific year, car etc so they can find it.
Also for that matter where can I purchase the adapter lead? Is this the wire kit to change over to a non-regulator system? Most are 20.00 from Wilcox or any of the vette parts distributors.
Does this all hook up to stock brackets and won't fry the stock wires?
And lastly, I don't have to change my gauge? On an earlier forum they said it might fry the gauge, and God knows I do not want to pull that apart again!! Sorry for all the questions I just want to make sure I do this right. All help is greatly appreciated.

terrys6t8roadster

My son went to change the battery on his 08 chevy P/U last Sunday up north during hunting season, he left the engine running so he wouldn't loose the radio memory and as soon as he disconnected the battery the engine shut off. The reason being the 08 runs off the battery and the alt charges it. Now drop back 4 decades to a 68 vette and you can take the battery out and still drive the car around until it runs out of gas as long as the charging system is good. This is because of the way the vehicle system is wired. Now putting a 100+ amp alternator in place of a 42 or 62 amp OEM 68 alternator and running the same 50 year old OEM 12 ga wire from the alternator to the starter is taking a chance. A stock 69 vette with A/C has a 62 amp alternator with an internal regulator which would not require and mods to mounting, belt and just some minor wiring changes at the alternator itself, easy to do, but not enough for any future upgrades to like electric fans, big stereo, etc. T

derekderek

you can also buy larger aftermarket rotors and staters and get a lot more amps out of your 10DN or 10SI original style alternators and have the correct look under the hood if that matters to you.

Rescue Rogers

what are your future plans? Do you plan on headlight upgrades, radio upgrades, electric fan upgrades, stereo upgrades? I did all these on my 68 with a 100 amp single wire and the little conversion wire but I put in a new Lectric Limited ignition and headlight wiring harness. No issues, but I want to add a voltage meter somewhere because the amp gauge isnt sure whats going on.

carriljc

Let me find my post with part numbers. Gimme a bit.

carriljc

After reading this response I think you might be better off with a GM 12si 94 amp alternator. It will require minimum wiring changes and stay within the limits of your preexisting wiring.
I used to have a 94 amp 12-si in my 68:
https://www.autozone.com/batteries-s...12352_486294_0

And here is a part number for Limited Lifetime Warranty unit at autozone: Part Number: DL7294-12
Alternate Part Number: GMK7294-12

You are probably just better off buying this harness for plug and play replacement.
https://www.corvetteforum.com/forums...on-harness.pdf

See responses to your questions below in BOLD RED. I recommend this course of action for you after reading your response.... I rewired mine but it does not seem like that is something you want to do.

Buttersvette

carriljc

Just a followup:
Yesterday, after working on my car for several months, I started it for the first time. Looked like the 140-amp CS-144 wasn't charging... I wiggled the connections and whatnot, then decided to swap in my old 94-amp 12si. So, I got it swapped over for some test driving.
The 12si works just fine but it has a really hard time maintaining voltage at idle (I idle at ~700 rpm). Actually, when at idle, and the Mark-VIII rad fan starts the 12si just is NOT able to maintain terminal voltage. It seems like EFI, Electric Fuel Pump, and then starting the rad fan at idle is just a bit much for the 12si capabilities.
When I'm at a higher rpm and/or driving around, then it maintains voltage fine.
Later, I cleaned up and fixed the connector to the CS-144 and swapped it back in. It maintains voltage at idle wonderfully. So, if you are in the process of upgrading alternators, and you have added electrical loads, then it would be probably worth it to go to a CS-144 and skip the intermediate steps.

Mooser

The biggest bonus to the CS144 is the output at lower RPM.
Lots of other alt's have lots of amps but only when rev'd up.
My electric fans at the largest draw and they're needed when I'm putt'n around town or in traffic not when the engine is turning over on the highway
M

SteveG75

EFI can also be very sensitive to voltage. Reason why I went to a 140 amp Powermaster for the EFI, fuel pump, elec fans. Adding a second charging wire from the alternator to a terminal block by the starter (use that for all my accessories wired direct to battery) was easy and stopped the ammeter from pegging when charging.