1 wire alternator and gauge

I don't know if this info will be helpful, but here goes. The only time the gauge will be pegged out is when there is an electrical load requiring 65 amps and above, not sure what additional electrical loads you have but IMO, it is always better to have too much alternator power/amperage than not enough.  I installed a 130 amp 3G Ford alternator, due to the double amperage output the 3G has over the original 65 amp 1G alternator, but it wasn't a good idea for me to keep the original ammeter's shunt type wiring. The shunt only has a 10ga wire that handles the charging/electrical loads from the alternator to the battery, while this is fine for a 55-65 amp alternator, it would be a "choke point" for the 130 amp alternator and potentially a fire hazard. The 130 amp 3G was required due to amperage increases caused by stereo system, dual electric cooling fans, electric fuel pump, aftermarket ignition and etc. I used a DC current clamp meter and found I was pulling over 120 amps with everything on, not good with a 65amp ammeter gauge and associated wiring. I originally read a post from PSQUARE75(Paul) where he sent his ammeter to rccinnovations.com and had him change it over to a voltmeter, after reading this post I decided to send (2) ammeter gauges in for the modifications, having one as a spare. The gauges look and perform great, here is a pic of what his modified gauge looks like: As a "crutch" you can remove the small 10ga wire from the shunt and replace it with a larger 4ga cable to handle the increase in alternator output but the gauge won't read correctly, thus leaving you with an installed gauge of no real use. I painted the volt meter's pointer fluorescent orange to match my other gauges and installed it where the ammeter was removed, it did require the positive side of the gauge to be powered through the ignition switch instead of being powered all the time like the original ammeter. The other terminal gets a ground wire attached. I hope this helps somewhat. Todd 

The shunt is located on the passenger side inner fender. One end of the shunt attaches to the battery side of the starter solenoid, the other end attaches to the "power distribution" stud mounted about 6-8" below the starter solenoid toward the alternator. Sorry, I do not have a pic available, I will try to find and post one.

Scott,

Interesting. I don't remember that on my 72. I'll have to check my 73. I think I do have that on the 73.
I looked at my 72 harness and I do have a small circuit breaker looking thing on my starter solenoid. Have to recheck it out today. I'm sure I'll come across it.
Thanks for posting the pics Todd.