Classic Instruments - Fully (En)Gauged
Classic Instruments Will Help You Monitor Your '67-'68 Mustang's Vitals With Ease
From the August, 2007 issue of Modified Mustangs & Fords
By Mark Houlahan
Photography by Mark Houlahan
We first met up with Classic Instruments at a trade show two years ago. John McLeod, Classic's owner, and Zac Compton, one of Classic's sales associates, picked our brains about Mustang gauges. It seemed that the guys in engineering were on the fence about their next project. Should they do a gauge cluster for the early Camaro or for the popular '67-'68 Mustang market? The '67-'68 market is undeniably hot, and while there's already a couple of different gauge solutions on the market, there's nothing like competition to improve a product line.
After discussing the market and talking them into putting the Camaro kit on the back burner (sorry, Chevy guys), we worked with the crew from Classic Instruments, including many e-mails and phone calls with Dave Falther, Classic's production manager, to work out their gauge program.
The Classic Instruments gauge...
The Classic Instruments gauge set features all electric gauges and includes the oil-pressure and water-temp senders, as well as the correct speed sensor. The fuel gauge is calibrated to use the stock Mustang fuel-level sender, so there's no need to mess with your fuel tank.
We begin our installation...
We begin our installation with the conversion to the Classic Instruments spec pressure and temperature senders. Disconnect the battery, make sure the engine is cold, and then remove the water temperature sender from the intake manifold. You don't need to bother with draining the coolant (just a little comes out because the sender is the high point of the cooling system), but if you have a detailed engine, consider a partial draining of the system.
The new sender provided in...
The new sender provided in the kit is threaded into the manifold in place of the original unit. While we've heard of people installing pipe fittings dry, we prefer a little thread sealant on the threads. Thread tape is OK (and all we had available during this install), but a liquid thread sealant is better.
Providing Classic Instruments with some points of contact for a dash bezel, and following up with measurements and wiring diagrams, as well as Classic's tooling time for mounting the gauges, took the better part of a year. At the end of all this hard work, Classic Instruments sent us a prototype, which you'll see in the photos, so we could test fit it and offer feedback.
Now Classic Instruments has a completed product that we think will be a hit. The new '67-'68 cluster is competitively priced, installs easily, and works like it should. The gauge cluster is available in three styles: the Hot Rod Series with a black face, white lettering, and an orange pointer; the White Hot Series with a white face, black lettering, and an orange pointer; and the G/Stock Series with a black face, mint-green lettering, and an orange pointer. We chose the G/Stock Series for our installation.
Once the sender has been started,...
Once the sender has been started, tighten it with a deep socket of the appropriate size. As you can see, we had to temporarily remove the distributor to get enough socket clearance (and for a better photo) due to the location of the sender in this aftermarket manifold. Most OE senders are on the driver side of the manifold, so this step will not be necessary.
The stock wiring is retained...
The stock wiring is retained for all gauge senders, so there's no need to add additional wiring underhood for the water-temp and oil-pressure senders. If you don't already have a tach feed wire inside the car, you'll need to run a wire from the coil negative terminal to the dash for the Classic Instruments tachometer.
The oil-pressure sender installs...
The oil-pressure sender installs directly in place of the original sender on this '68 Mustang. If your Mustang has a small "idiot light" sender for some reason, you'll have to use the included brass fittings to space the sender out and away from the block, like the OE piece shown here. Assemble the provided brass adapters in the kit, and thread it into the engine block to attach the sender in a position similar to the one shown here, clearing the exhaust and power steering (if equipped).
Our photos are of a preproduction unit, so there are some minor changes to the pieces on the market now. We note those changes in the captions for you.
Since the speedometer in the...
Since the speedometer in the Classic Instruments package is electric, a speed sensor similar to what is used on modern Fords is required. Carefully jack up your Mustang and support it with jackstands to remove the old speedometer cable from your transmission. You will remove the speedometer cable completely from the car later, once the factory gauge cluster has been removed.
This is the early design of...
This is the early design of the speed sensor that came with our prototype kit. The sensor is hardwired with three wires that must be elongated to reach the dash. We used extra wire we had from our Factory Rive Racing Roadster build project and soldered and shrink-wrapped the wires.
The end of the speed sensor...
The end of the speed sensor is similar to the old speedometer cable. You will need to transfer your original speedometer driven gear to the end of the speed sensor or buy a new one.
The drive rod is inserted...
The drive rod is inserted into the speed sensor first; then the driven gear slides over the sensor end and is mated to the drive rod. Finally, the gear is retained by the original clip from your speedometer cable.
This is the updated Classic...
This is the updated Classic Instruments speed sensor included with production kits. The sensor still requires you to swap the speedometer driven gear and retaining clip, but it's no longer hardwired. Instead, there's a weatherproof quick connection on the end, allowing easy disconnection for servicing. The kit comes with enough wire to route to the dash area also, so you won't have to provide your own wiring for the speed sensor like we did.
When installing the speed...
When installing the speed sensor, be aware of moving shift linkages, exhaust system components, and your parking brake cables. Route the wires from the speed sensor forward to the firewall; then up the firewall through an existing dash opening, such as the speedometer cable hole (or drill for a new one and be sure to use a grommet).
To make taking photos easier...
To make taking photos easier and to give us a little more working room, we quickly removed the aftermarket steering wheel from our '68 coupe. It's not necessary to do so to swap the gauge cluster, but it does make the job a bit easier.
Begin the removal of the gauge...
Begin the removal of the gauge cluster by pulling the in-dash heat/air control panel. The panel can stay connected to the wiring harness and control cables, but it needs to be pulled out a bit so the gauge cluster will clear upon removal.
Remove the screws retaining...
Remove the screws retaining the cluster itself (and the large retaining nut on the rear at the center vent/block-off plate, if still there); then pull the cluster assembly out a few inches. Reach behind and unthread the speedometer cable from the speedometer head.
Once the speedometer cable...
Once the speedometer cable has been freed from the cluster, you can continue disconnecting the wiring pigtails from the gauges themselves.
Here's the original '68 cluster...
Here's the original '68 cluster compared to the new Classic Instruments option. The water-temperature and oil-pressure gauges are swapped end for end in the Classic piece, so that might take a little getting used to when scanning the gauges. The fuel level now resides in the center, where the optional clock was located. You might notice that Classic Instruments uses a '67 housing. While functionally the same (and it will install in a '68), the owner of our '68 project preferred the '68 housing. Luckily, his was new. We simply modified it to work with the Classic Instruments hardware. Classic Instruments offers the '68 housing, as well as the brushed-aluminum and woodgrain deluxe interior versions, for a slight upcharge through its custom build program.
The only item you'll need...
The only item you'll need from your original gauge cluster assembly is the wiper-motor switch. Remove the chrome knob via the proper Allen wrench, and detach the switch from the cluster by removing the retaining screws.
Transfer the switch and mounting...
Transfer the switch and mounting screws to the new Classic Instruments version, and reinstall the chrome knob on the front.
Don't forget to disconnect...
Don't forget to disconnect the single wiring connector from the wiper-motor switch at the top of the gauge cluster. The cluster is now free to be removed from the car.
One thing we noticed in our...
One thing we noticed in our inspection of the prototype was that, unlike the OE cluster, the Classic Instruments version was missing any sort of reinforcement or support for the three mounting screws at the top.
After forwarding a few photos...
After forwarding a few photos to Dave Falther at Classic Instruments, the crew came up with this additional brace that allows the top row of screws to secure the cluster to the dash.
This brace will come preinstalled...
This brace will come preinstalled on all production units.
For our early prototype gauge...
For our early prototype gauge cluster, the wiring for the dash had to be modified by cutting the cluster plugs off of the harness and crimping the provided terminals onto the original wires. The terminals were placed into the provided plastic connector shells in the proper order, according to the wiring diagram.
Any unused wires were simply...
Any unused wires were simply capped with a length of heat-shrink tubing. Heat the shrink tube, and squeeze the end shut with a pair of pliers for a weatherproof seal that will not short the circuit.
Our completed wiring makes...
Our completed wiring makes the Classic Instruments cluster a plug-in, albeit a permanent one (who wants to go back to stock gauges now?). The wiring provided on the cluster is more than a foot long, making for easy wiring connections with the cluster out of the way, unlike the stock offering, which must be done almost by feel.
The included instructions...
The included instructions explain in detail how to measure for the correct speed. Read your indicated speed on the included chart and follow it across to the proper dip switch orientation. Regardless of the type of gears, the tire size, or transmission type, you can easily calibrate the speedometer in a few simple steps.
After we were done, we discovered...
After we were done, we discovered this green-with-yellow-stripe wire was cut out of the connector and sealed off. Doing this prevented our interior lights from working, so we had to remove the cluster and connect these two wires-as they were in the original connector-for the dome lights to work again.
After we finished the wiring...
After we finished the wiring and made some notes for the guys at Classic Instruments, we suggested offering a pigtail adapter to those who frown on cutting the stock dash harness. Classic Instruments happily obliged and will send this pigtail with all gauge kits. Now you can either use the company's original connector with your aftermarket dash wiring (such as a Painless harness), or if you have the stock wiring, you can use the included jumper pigtail to make the gauge cluster a plug-in for your stock wiring. How cool is that?
With the cluster wired, the...
With the cluster wired, the speedometer calibrated, and everything else double-checked, it's time to secure the new gauge cluster into the dash of our '68 and reassemble the heater controls and steering wheel.
What Do You Get?
Since our installation was based on a preproduction prototype, we want to detail exactly what you get when you open the Classic Instruments box.
'67-'68 Mustang Gauge Cluster
• Built with a new reproduction bezel ('67 style)
• 12-volt electric gauges are premounted and prewired
• Speedometer: 5 inches, 140 mph (without trip odometer
• Tachometer: 5 inches, 8,000 rpm
• Water temperature, fuel level, oil pressure: 211/44 inches
• Stainless steel bezels with real curved-glass lenses
• Wiring harness made from GXL 18-gauge, color-coded wires
• Terminated for aftermarket wiring, OE wiring adapter included
• Sending units for speedometer, temperature, and oil pressure are included
• Fuel gauge operates with stock 75-10-ohm Mustang fuel sender
• Available in three styles:
Hot Rod Series, HRMU67, $1,150
Black dials with white lettering and fluorescent orange pointers
White Hot Series, WHMU67, $1,150
White dials with black lettering and fluorescent orange pointers
G/Stock Series, GSMU67, $1,150
Black dials with mint-green lettering and fluorescent orange pointers
• Built in the United States with a five-year product warranty
• Custom colors; optional gauges and styles can be built (extra charge and time needed)
• Senders available for different makes and models of any engine and transmission