Probably more of an electrical question rather than performance, but haven't received any help from the wiring forum. I want to put a cutoff on my alternator and haven't done this in over 30 years. On a 72 Chevelle, is there a neater way than going all the way to the alt? And also, isn't it the white wire that I need to splice into? This car has an external regulator. Thanks

The way I have mine wired up and it works is....

Main charging wire from back of alternator and positive from battery to one side of the switch.

On other side of switch I have the main power wire running to the starter and I also have my fuel pump relay on the same side.

I am not sure if this is the only way or best way but it shuts the car off and kills power to everything. I can make a picture if you need but its pretty simple.

Dave

Are you running a braker points distributor?? ...if so tap a on/off switch on the wire from the coil to the distributor. (old style 60's kill switch)

If you have a HEI, do the same by installing a HD on/off switch on the power wire to the "batt" terminal of the distributor.

Just curious, what is the purpose of cutting off the alternator?

Just curious, what is the purpose of cutting off the alternator?

Theft deterant. I think

No it's not theif protection, it was a way in the old days of freeing up some horsepower when people run generators. all you have to do is put a switch in the field wire.

If this is for freeing up horsepower,it will be a total waste of time. You won't see any improvement by way of ET or MPH. If any thing you stand a better chance of hurting performance than helping. Your electrical system (including your ignition coil) actually operates at about 14v with the alternator. When you disable it you will be on battery power alone probably no more than 12v. So now you just lowered coil output at a time when you need it most. Instead of wasting your time on this switch,spend it tuning your car.

You could invest in a big voltage "coil only" dedicated battery that is turned on by the same toggle that deactivates the alternator output.
My experience has been that you go slower if the coil voltage drops below the 13 volt range.
ps. you need a special charger for the high volt batterys if I remember correctly.

Guys, thanks for all the input. Like I've said before on here, I'm 53 and been away from the scene for a while. Didn't think about the voltage drop with the MSD. That's what is so great about this forum. I'm kinda old school and need to be updated quite often. Going this weekend with a new set of Mickeys. I know there's an 11.75 in this thing if I can a decent 60ft out of it. Thanks again.

I tried that in my racing days in Stock Elim. I had the alt field wire wired through the dimmer switch. I couldn't find any ET improvement with it.