Here's the tricky part. If you decide to run the MSD control box, just plug things in according to the instructions. However, to use the factory Ford Duraspark box and save some bucks, make a jumper harness. The harness from MSD, PN 8866, is used from the distributor to the MSD box. We found that by hooking the green and purple wires on the harness to the factory plug and grounding the third wire, the unit functioned perfectly. MSD says that it's working on a direct hookup jumper harness to aid installation.
