I have recently finished wiring my 66 with a new harness from American Auto Wire. It is a one wire alternator setup. It took me quite a long time to get everything just right with wire loom and everything. Anyway, I have added two electric fans that connect to the junction block next to the battery. Would it be ok to just add a second 10 gauge wire from the alternator directly to the junction block without going through the horn relay? Or should I just redo the original alternator wire with an 8 gauge. It seems from reading other posts on this site that the stock wiring won't handle the fans which is why I am asking.

Thanks.

What amperage is your alternator?
If you have a higher amperage you should install a larger wire. 8 ga is probably sufficient. This wire should go from alternator to horn relay, from horn relay to junction block, from junction block to battery.

In answer to your question, yes, you can run another wire directly from the alternator to the junction block if you leave the original wire in place and hooked up. If you do this you should also add a wire from junction block to battery.

I would just do it all with a new 8 ga wire.

You really should run 8 guage to the horn relay from the alt and get power for the fans from there. Leave the 10 guage from horn relay to junction block. The smaller guage from horn relay to junction block will slow the drain and recharge rate on the battery, which is good for the battery.

You can run another wire or six wires if you want, they will all work but some wiring is better than others. There are reasons the engineers layed out things the way they did.

Thanks for the advice. I guess I was asking about the secondary wire as just a temporary solution until I get around to doing it right. I always try to do things the right way so I will redo the wiring soon. I just want to get the car running to keep my motivation going. Thanks again.