[ERASER5]

Sure, you can keep the yellow wire hooked to the starter. It doesn't hurt anything. That is how the original wiring is.

However, the original coil wire-to-firewall was a resistance wire that cut the voltage to 6 volts. The yellow wire to the starter gave you a full 12 volts at start up for better spark until the starter is released.

A proper HEI power source will NOT be a resistance wire. It will be a normal wire supplying 12 volts to the coil at all times(when the key is on or starting). The yellow wire to the starter is redundant and not necessary. Check any of the FAQs on HEI conversion.