bluecars

Just got this a this trk and it had 6al stuff in it I have removed the 6al box the 2 step box and replaced it with 7al3 red box now I have every thing working but the shifter solenoid I noticed it was still connected to the msd rpm control box so I disconnect it question is please explain how to wire the solenoid to the 7al3 I understand it goes to the ras output but is there a certain way it needs to be wired I don't want to mess anything up if I need a relay in system please explain how to wire if it makes a difference it is spring loaded with the big button on the end 2 wires red and black thanks in advance Billy