I have been chasing a 2.5 V voltage drop at coil with ignition in RUN so I am trying to map wires and read many posts but do not see any discussion on this topic.
I have seen 2 pics in these forums related to different issues that show a red jumper wire from orange (alternator) to red (battery)....

Orange wire?

Might be the orange wire from starter solenoid to ballast resistor and eventually to coil positive. If so, it would transfer full Battery voltage to coil during start. The orange wire on mine is connected to the terminal marked "I" on starter solenoid. I've been...