How to Install a Classic Mustang Rally Pac

How to Install a Classic Mustang Rally Pac

Last Updated November 28, 2023 | Bill Tumas

If you’re looking to elevate your Classic Mustang's style and functionality, a rally pac adds a tachometer and clock to your Mustang while maintaining the factory aesthetic. Through this step-by-step guide, we’ll walk you through the installation process, ensuring a seamless integration of the rally pac into your classic Mustang’s dash area. Dive into the Classic Mustang Rally Pac installation process and add some helpful Mustang gauges to your ride.

Classic Mustang Rally Pac Install Instructions

We chose the 1964-1965 8000RPM Ford Rally Pac for this Classic Mustang installation. Your rally pac might be different from the one we chose, but the installation should be similar for most models. Just make sure the fitment is correct for your Mustang’s year.

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Parts and Tools Needed:

  • Phillips Head Screwdriver
  • ⅜” Ratchet
  • ½” Socket
  • 5/16” Wrench
  • 10-32 Nut
  • Adhesive Rubber Spacer

Step 1: Disconnect the Battery

Since this installation requires working with your Mustang’s electrical system, be sure to disconnect the battery before you begin.

Disconnecting Classic Mustang battery

Step 2: Remove Door Sill Panel

Using a phillips head screwdriver, remove the screws holding the door sill panel in place. Remove the panel from the car and set it aside.

Removing Classic Mustang Door Sil Panel

Step 3: Remove Kick Panel

Use a phillips head screwdriver to remove the screws on the inside face of the kick panel. Remove the kick panel and set it aside.

Removing Classic Mustang kick panel

Step 4: Locate the Black and Blue Wires Under the Dash

Head underneath the dash area. There will be a bunch of different color wires down there, but you’ll want to find the connector at the end of the black and blue wires. Once you have located them, take the connector at the end of the blue and green wires coming from the rally pac and attach it to the black and blue wire end.

Locating Classic Mustang wiring

Pro Tip: If the black and blue wires are already connected elsewhere, install rally pac wiring between the currently attached wires, creating a forked connection.

Step 5: Detach Instrument Cluster

Use a phillips head screwdriver to remove the screws holding the instrument cluster in place. Pull out the cluster and rest it on the steering column.

Removing stock Classic Mustang instrument cluster

Step 6: Connect Illumination Wiring

Behind the instrument cluster, locate the blue illumination power wire. Attached to this wire will be a grounding wire. Attach the power wire to the connection point pictured below. Loosen the screw on the factory grounding point at the rear of the wiring compartment, and connect the grounding wire, then re-tighten the screw.

Connecting Classic Mustang Rally Pac wiring

Step 7: Connect Wiring Harness to Ignition Switch

Locate the ring terminal wiring from the rally pac. Attach the ring terminal to the stud on the back of the ignition switch. There will already be a nut on the back of the stud, so instead of removing it, it’s best to slide the ring terminal onto the stub and tighten it with a second nut. Use a 10-32 nut and put it on the stud behind the ring terminal, then tighten it down with a wrench.

Connecting Classic Mustang Rally Pac wiring to ignition switch

Step 8: Connect Wiring Harness to Coil Wire

Locate the final ring terminal connecting wire from your rally pac and connect it to the negative terminal of the coil. Attach a nut on the other side of the wire, and tighten it down with a wrench.

Connecting Classic Mustang Rally Pac wiring to coil

Step 9: Reroute Coil Wiring Connection

Follow the factory wiring harness away from the coil and feed the rally pac wiring through the back engine wall into the interior. If there is not already a hole for the factory wires, you may need to drill one.

Rerouting Classic Mustang Rally Pac wiring

Step 10: Plug In Rally Pac to Test Connections

Connect the rally pac wires to the corresponding colors. The red wire with the green connector will go to the coil. The black wire goes to the ignition. For the wiring harness installed in step 4, connect the two blue wires with red connectors to the two outside holes of the red harness plug. The black wire goes to the ground connection, and the blue wire attaches to the blue connector.

Plugging in Classic Mustang Rally Pac wiring harness

Step 11: Test Rally Pac Instruments

Reconnect the battery. As soon as the rally pac is plugged in, the clock should start working. Close the door and make sure the clock is still functioning while the door switch is engaged.

Start up the car and rev the engine is neutral to test the tachometer and make sure it is registering correctly.

Testing Classic Mustang Rally Pac instruments

Step 12: Install Rally Pac Wires

Disconnect the battery and unplug the wires connected to the rally pac. Fish the wires through the bottom of the dash into the compartment behind the instrument cluster, then reconnect the wires.

Reconnecting Classic Mustang Rally Pac wiring

Step 13: Reinstall the Instrument Cluster

Reinsert the factory instrument cluster into the factory dash compartment and reinstall the factory screws. Tighten the screws down with a screwdriver.

Reinstalling Classic Mustang instrument cluster

Step 14: Mount the Rally Pac

Find the mounting bracket included with your rally pac, and insert an adhesive rubber spacer between the bracket and the steering column. Install the screws on either side of the mounting bracket and tighten them down with a screwdriver.

Mounting Classic Mustang Rally Pac

Step 15: Reinstall Kick Panel

Reinsert the left kick panel into the factory location and tighten down the screws.

Reinstalling Classic Mustang Kick Panel

Pro Tip: Make sure to hide any wires beneath the dash area before reinstalling the kick panel.

Step 16: Reinstall Door Sill Plate

Place the door sill plate back into the factory location. Tighten down each of the factory screws.

Reinstalling Classic Mustang door sill panel

Step 17: Set the Clock Time

Pull on the small chrome piece at the base of the clock until it extends. Turn the dial until the clock displays the correct time.

Setting the clock on a Classic Mustang Rally Pac

Congratulations, You’re all done!

Make the Most of Your Classic Mustang Rally Pac Upgrade

With your Classic Mustang Rally Pac installed, you can hit the open road with a new level of precision and style. The vintage design instantly captures attention, becoming a visual highlight of your Mustang’s interior. The integrated tachometer and clock provide real-time RPM monitoring, enabling you to maintain control and stay on schedule effortlessly. Seamlessly blending with your Mustang's dashboard, the Rally Pac preserves the authenticity of your classic car while adding a touch of modern functionality. Check out our wide variety of Mustang rally pac styles and options for 1964.5-1968 models and give your Mustang the interior update it deserves.

This article was researched, written, edited, and reviewed following the steps outlined in our editorial process. Learn more about CJ's editorial standards and guidelines.