Modernized Engine Wiring
I used a smaller relay box out of a 90's Voyager, same idea. In my 67, I "tossed the towel," converted the ammeter to volts, and ran a nice big no6 right from the alternator to the start relay. Bulkhead is all bypassed.
Bill I don't understand exactly what you did, there with the diodes. You said "back to back," did you mean parallel? I do understand how external shunts work, I just didn't catch how you did this.
Draw us a diagram, maybe?
Thanks.