Do-It-Yourself Plug Wires

You can test fit all the wires at once or simply sort them according to length. The longest wires go to the plugs in the front of the block (obviously). Plug the boot over the plug in the proper cylinder and route the wire all the way to the proper distributor terminal with a little extra length to spare (just in case).

You can cut the plug wires with standard wire cutters. Just make sure to leave 1/4- to 1/2-inch—depending on the brand and type of terminal—of the conductor wire to properly attach to the terminal.

This is what MSD calls its “Dual Crimp” terminal. It has crimp points for both the main wire and also the core. Once the main wire is properly crimped, use a pair of needle nose pliers to crimp the core wire.

MSD also includes this multi-purpose tool with its plug wire kits. You can position the wire in the “strip guide.” Score the outer silicone coating with a razor blade. The tool doesn’t allow you to cut all the way into the core wire, protecting it from damage. This also helps you expose the correct length of core wire to work with the terminals.

Another option is this stripper/crimper tool also available from MSD. In this position, it will strip the insulation from the wire without damaging the core. The next slot up is used to crimp the terminal to the wire.

By twisting the cut end of the wire in a counter-clockwise direction, it will pull off without damaging the core.

This is the standard terminal that MSD also sends with the kit. It creates an electrical connection between the core wire and the terminal by stripping back the insulation and bending the core back against the outside of the insulation before crimping the terminal to the wire. Then the terminal is bent to fit the boot

The multi-tool also includes a crimper. Simply place the wire and terminal between the two halves and crimp the entire assembly in a bench vise like you see here.

It can be difficult getting the boot to slide over the terminal and wire. Dielectric grease (which conducts electricity) works well, or you can use a small squirt of WD-40.

The boot simply slides right over the terminal, just use caution not to bend the terminal or tear the silicone boot.

MSD also includes this tool with numbered collars to help you quickly number the wires. Remember, the firing order for a Chevy small block is 1-8-4-3-6-5-7-2 and the rotor turns clockwise in the cap. On a Ford the firing order is 1-3-7-2-6-5-4-8 and the rotor turns counter-clockwise in the cap.

With race headers it’s usually easier to run the wires down the back of the block and underneath the header’s primary tubes. All that’s left to do now is loom up the wires so that they won’t be touching each other (which helps eliminate the chances of electricity jumping from one wire to another).