With the new reproduction Rally-Pac from CJ Pony Parts, you can add the factory's sporty tach and clock combo to your '65-'66 Mustang.
There's always one last item that makes a project perfect. The handblown glass Christmas-tree topper, the fancy ribbon around a gift box, or even the cherry on top of a sundae are examples that come to mind. For Mustang Monthly's Project '66, the one item we wanted to top off our restoration was a Rally-Pac. The Rally-Pac Ford offered in the '60s became a much-coveted option through the years, and having one in your restored Mustang was icing on the cake. Though our project car has been completed and on the road for more than a year, we've added a few items as they became available, such as the newly reproduced console trim that allowed us to finally install a console. Now we can do the same with a Rally-Pac.
Until recently, the problem has been finding a decent one in restorable condition, sort of like finding someone under 18 at a Barry Manilow concert. But things have begun to shape up for us Mustang enthusiasts (although I can't say the same for Barry). The highly sought-after Rally-Pac is now available as an accurate reproduction for '641/2 to '66 Mustangs (both low- and high-profile models) in 6,000- and 8,000-rpm tachometer versions. A brand-new exterior-case casting (wrinkle-finished like the original) is the foundation for all new internals as well. An accurate electronic air-core-movement tachometer and a quartz clock assembly with all new lenses, chrome trim, attaching hardware, and wiring are part of the kit. The tachometer and clock faces are silk-screened like the originals, though they are now backlit for easier viewing at night.
Installation isn't difficult (just some minor wiring and turning a screwdriver or ratchet gets the job done) and you can add the classy look of a Rally-Pac to your Mustang in about an hour. It comes only in black or white, so if you want to color-match the Rally-Pac to your interior (only correct for the low-profile model in cars with the Interior Decor option), we suggest picking the white model and buying a can of interior spray paint so you can color-match it yourself. Our Interior Decor color is black, so we didn't need to refinish the exterior housing. If you decide to color match yours, use light coats of paint to prevent losing the wrinkle-finish look.
We picked up our '66 Rally-Pac from CJ Pony Parts (PN RP5, $434.95). CJ also carries the '65 high profile-model.
4 You can probably snake your hand behind the gauge cluster to make the connections, but if you carefully label the wiring going to the back of the cluster, it's easier to disconnect the wiring from one side of the cluster and let it hang out of the way. You'll have to unscrew the speedometer cable to do this. Notice the towel over the steering column to protect the paint. | 
5 With room to work, start with the underdash harness installation. The first part of the harness deals with the clock power and connects in series with the doorjamb switch. Make sure you've disconnected the battery before unplugging the doorjamb switch. The green wire with the green end is the original wire to which you will connect the clock feed. | 
6 The remaining underdash wiring connects near the ignition switch, so carefully route the harness in that direction. The blue wire from the Rally-Pac underdash harness will connect to the dash illumination circuit. This is a red plug with three female bullet terminals by the ignition switch. Connect the blue wire to one of the three available spots in the connector. |
7 The black ground wire (with the small ring terminal soldered to it) is the main ground lead for the Rally-Pac and needs to be connected to a clean, secure ground path. There are plenty of dash screws you can use, but we simply added it to the several other ground wires found at the right dash brace. The red wire with the green connector is not used in the V-8 application. | 
8 Two wires come with the main Rally-Pac harness that you can disconnect and install separately of the Rally-Pac. One is the power feed from the ignition switch and the second is the tachometer signal wire. The short black wire connects to the stud on the back of the ignition switch. Temporarily remove the retaining nut, then slide the ring terminal of the short black wire over the stud and re-secure the nut. Now you can reinstall the gauge cluster and kick-panel trim. | 
9 The long black wire is the tachometer feed and needs to pass through the firewall. The instructions suggest the accelerator-pedal-rod seal, but we found enough gap in the A/C-hose grommet to pass the wire through at this point. You can also drill a small, discreet hole to pass the wire through. |