WIRE MSD DISTRIBUTOR TO STOCK WIRING
I have an MSD distributor (#8579) in the Fastback and I can run with all MSD set up or with a Ford Duraspark II ignition box (blue connector). I bought an extra MSD distributor 2 wire connector (like the one from the MSD mag pickup), and connected it to the distributor wires that went to the Duraspark distributor. The Duraspark pickup has three wires and the MSD pickup has two. The Duraspark third one is a ground which I merely connected to the engine block on a convenient bolt. If you want, I could tell you what color wires I connected up.