Electrical gurus.... need help with alternator hookup
Yes, IGN "run" goes to both the regulator "I" terminal and to one field connection. Does not matter which. It is important that "switched ignition" has now drop, IE very close to battery voltage, as this is also the regulator sense line
Same regulator will work with the 100A. I don't recommend you run a 100A with the factory bulkhead, IE do the ammeter bypass "Fleet" (police and taxies, etc) had modified wiring that went around the bulkhead connector
Read the "MAD" article to get an idea of the ammeter/ bulkhead problems:
http://www.madelectrical.com/electricaltech/amp-gauges.shtml
Here's the diagram: