[FAST Tech Maxwell]

Which MSD box do you have? Is it a Digial 6?

If so, then when you apply 12 volts to the Pink wire it retards the timing for the nitrous.

You can hook the Pink wire to the same location as the Red wire for the ZEX nmu. This will retard the ignition timing anytime that the Arm switch is activated.

If the Arm switch is not activated, then you have full ignition timing to run good on motor.

Remember to follow the ZEX tuneup chart in your kit instructions for the proper timing retard setting.