When changing spark plug leads, either for maintenance issues or when installing a new coil, you can insure you're getting maximum voltage and minimum resistance to your spark plugs by soldering the lead's internal wire to the brass coil insert.
Trim back the outer wire sheath to exposed about 3/16" of the wire. After working the wire through the brass fitting, bend and spread the wire threads flat to the brass, then solder.
After a dab of dielectric grease on the fitting, plug the lead into the coil's receptacle. Hot sparks!
