Greetings from Oregon, I have a problem and hope one of you can help me. My 68 GT 350 has the factory tach. There are three wires coming form the firewall. The wires are as follows; One Red with white stipe One Red with Green stripe One Thick Black wire. If you have any idea what they hook up Please let me know. I am attempting to hook up an MSD ignition system. If anyone has advise PLEASE let me know. I do not want to fry anything. Very Best, Gary Fuszek