[Don]

On the 351W, already had the MSD-6A installed and replaced the Ford electronic distributor with the MSD Billet , #8584. Purchased from Summit for $189. Nothing unusual about the wiring, but the interface connection harness from Ford to MSD is eliminated. Yes, with the timing and advance options available on the MSD Billet, made a substantial difference in overall performance and starting a hot engine.

Seems also with a total MSD system the components are in synch with each other and the potential of any wiring difficulties are greatly reduced.