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74 Posts
Discussion Starter · #1 ·
I currently have the traditional setup with the alternator with external voltage regulator on the drivers side of the vehicle.

I have just added a 135 Amp Alternator to my 67 Chevelle Malibu. I upgraded the alternator since I added a stereo system and may add an electric fan radiator set up.

Currently my wiring on the 67 is the traditional
wiring with the alternator output wire running to the splice (near the drivers side)and then the Horn relay on the drivers side of the Chevelle.

My question is should I change the alternator output wire to say an 8 guage wire. One auto electric supplier suggested running an 8 guage wire as an upgraded alternator output wire to a junction box, then run a 10 guage wire to the horn relay (this would mean cutting off the original alternator output wire leading to the splice junction). Then using the remainder of the splice wire to have the wires running back to the battery and voltage regulator.

Or, will my current wiring set up be sufficient with the 135 amp alternator.

Another option for future consideration is what is outlined at Mad Electrics "New System" wiring
arrangement when using a 3 wire internal regulator
Alternator, like a Delco 12 SI. See this wiring
arrangement at:

My initial question is whether, if keeping the older wiring system, I should upgrade my alternator output wire. The person who sold me the
135 amp alternator (alterstart) indicates that my original wiring should be fine.

Advice please.


Ken McDee

Premium Member
19,960 Posts
I like the first guy's answer about using the 8 gauge from the alt to a junction block. Is the alt still a traditional 3-wire unit - appears so since you're still using the voltage regulator. I'd certainly upgrade the wiring on a 36 year old system.

I have a 135amp one-wire unit on my 67 and run an 8 gauge wire to the battery and a Painless CIRKIT BOSS 7 accessory unit 70207 for my extra needs. It uses a 10 gauge wire to connect to the battery through a circuit breaker. Since you may be adding future electrical components, you might check into something like this to take the load off your current fuze box.
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