Steve Baur
Former Editor, Modified Mustangs & Fords
September 11, 2014

There are those who love the classic looks of the early Mustang, and there are those who love the experience behind the wheel of one. And still there are those enthusiasts who love the lines, but believe the driving experience could be improved. Sure, there's something to be said for enjoying the classic experience, but that's not for everyone, and certainly not the goal for Mustang Monthly's newest project, Colt of Personality. No, this '66 fastback is going to offer a more current driving experience thanks to a bevy of modern enhancements.

Rescued from our former sister publication, Modified Mustangs & Fords, Colt of Personality has been modified from day one to excel in all areas over the original design. The project is about halfway through its metamorphosis from mundane Pony to thoroughbred performer, and we plan to bring you regular installments as we forge ahead to completion. Here is a brief review of how the project started, and where it has been so far.

Out of the Gate

The plan was to start out with a running and driving car. That way we could do before and after testing as well as modify the car while occasionally being able to drive it. To that end, we found a '66 Mustang fastback in reasonably good shape. It was black on black with a four-speed transmission and a 289 small-block engine between the shock towers. It wasn't a numbers-matching vehicle—we'll leave those to the collectors—so we were ready to lay out the modifications to make it handle better, ride nicer, and move a whole lot faster.

To get an idea of what it could do as-is, we took the car to Gainesville Raceway in Gainesville, Florida, and did some baseline dragstrip numbers on street tires. For what the car was, it pulled a respectable 15.4 seconds at 93 mph while hampered by a one-wheel-peel traction deficit. There was probably a 14 in it if we could get the power down, but the 289 overwhelmed both the open differential and the very old, very dry, 14-inch tires.

On the road course, we weren't concerned with getting a good time nearly as much as we were staying in the seat while cornering. It was a struggle to say the least, even with a seatbelt. The stock seat offered no lateral support, and the slick vinyl upholstery let the driver slide around. Beyond that, there was absolutely atrocious body lean, and the front tires often lost most of their contact patch. It was a mess, to say the least.

Time For Change

With our baseline testing out of the way, we charged forward with the modifications, making our first stop at Graverobbers Sheet Metal in Cumming, Georgia, to have a set of the company's mini-tubs installed. While the car was there, we also had new rear quarter-panels, new trunk panels, and a rear framerail done, as well as a new taillight panel—the previous owner had modified the light openings to fit a pair of Oldsmobile taillights in the car.

From the Peach state it was back to the project's home base in Florida where we met up with the staff at Gillis Performance Restorations (GPR). Owner Rusty Gillis agreed to oversee the project, starting with the installation of an independent front suspension and torque-arm–based rear suspension from Total Cost Involved (TCI) Engineering.

During the front suspension install, we realized there were some big structural problems with the car that were hiding behind the sheetmetal. While one of the front framerails hid some rust, what was more alarming was the improperly repaired front floorpan that was no longer connected to the front framerails!

And so GPR basically cut the front end off of the car and rebuilt it with parts from National Parts Depot. New framerails, aprons, and a sealed-up cowl panel gave us a great base on which to install the TCI Engineering front suspension. Moving toward the back of the car, GPR installed new seat pans and a rocker before performing the installation of the TCI Engineering rear suspension. Needless to say we now have the most solid of foundations to build on.

01. Our new project was well on its way to becoming a Shelby Hertz tribute, and was really only missing the gold stripes. It did have some Oldsmobile taillights out back that were not going to pass the Shelby faithful’s muster, and it didn’t agree with our taste either.

02. As you can see, the stock handling was not confidence inspiring. It plowed hard and often when going through the turns, and the steering was incredibly vague. None of this is surprising, considering how good even the most inexpensive cars of today have gotten over the last 50 years.

03. Given the fairly old and dry state of the 14-inch rubber on the car, it wasn’t too hard to slide out the back end for some action photography. In the end, we plan to have a classic-looking Mustang, but one that gets around the turns much better and safer.

04. A compression check revealed that the 289 mill was in good shape. Beyond that, it was a mystery as to what was inside it. As you can see from the picture, the intake manifold was upgraded to a Cobra dual-plane and the engine benefitted from dual exhaust.

05. One of the first orders of business was to replace the rear framerail that was rotten. We knew this to be the case on purchase, and the former owner gave us a replacement rail. Pictured here at Graverobbers Sheet Metal, our Colt Of Personality project was set on the company’s jig to ensure all work was completed with precision.

06. What started out as a mini-tub job and framerail replacement turned into new quarters, trunk drop-offs, wheelhouses, and taillight panel replacement. Here you can see Graverobbers has modified the framerail as part of its mini-tub kit.

07. The finished mini-tub looks exactly like stock, just a little wider so we can fit some bigger rubber out back.

The Driving Force

As we had removed the small-bock Ford engine and four-speed transmission prior to dropping off the car at GPR, we thought long and hard about what we wanted for a drivetrain. It needed to be powerful—we plan to enter the Pony in one of the Optima Challenge's qualifier events when we're done, and the current competition packs a lot of muscle. Driveability was also a major concern as we wanted to get into the car and be able to drive anywhere. With that in mind, we turned to Ford Racing Performance Parts for one of its Coyote 5.0L crate engines and Controls Pack. With 412 hp of overhead-cam goodness it offers a smooth idle, as well as a great base for future modifications.

As the Coyote offers a 7,000-rpm redline from the factory, it's hard for the current crop of aftermarket five-speed transmissions to shift quickly at that rpm, so we had to step up to the T-56 Magnum from Tremec. The Magnum has a number of internal changes that allow high-rpm shifting, and we plan to do plenty of that. Connecting the Coyote to the Magnum is a QuickTime bellhousing and a Centerforce DYAD dual-disc clutch. With the DYAD clutch, we'll have plenty of holding capability should we opt to add a power adder down the road.

After talking with the staff at Wilwood Engineering, the braking system was upgraded to a set of 14-inch front and 13-inch rear disc brakes. We also opted to use the company's full-floater rear disc upgrade and to do that, we went to Speedway Engineering who fabricated one of the company's full-floater housings and supplied us with the floater hubs. Speedway has worked with the TCI Engineering components before, and knew just where to weld the new brackets for the suspension on the housing.

We were able to fit the Coyote and six-speed into the car, and it dropped right into the TCI Engineering crossmember. We will have to relocate the master cylinder because of the width of the engine, and build a new transmission tunnel to fit the taller six-speed gearbox between the seats.

Still To Come

Currently, the car is undergoing a few body mods that we hope to show you, and we're also waiting on its custom wheels to arrive from Boze Forged. There's the custom transmission tunnel to build, the fuel system, a new steering column, wiring, and more left to finish. Gillis Performance Restorations will be handling the body and paint once all of the mechanicals have been sorted out. When the project is complete, we plan to take it out to some local shows, some local autocrosses, and some local road courses to experience all that these modifications have to offer. Come along for the ride.

08. Prior to installing the TCI Engineering front suspension, our Colt had the frontend rebuilt, courtesy of Gillis Performance Restorations. With a performance-based, independent front suspension from TCI Engineering going on shortly after, it was essential that we start with a solid foundation. In addition to having some rust up front, we found poor floor replacement repair work left the front ’rails more or less floating under the car as they were never welded to the floorpans.

09. The TCI Engineering front suspension bolted right up after the crossmember was welded in place. TCI Engineering sent us double-adjustable coilover shocks for the ultimate in adjustment—the company offers a number of options depending on your vehicle needs.

10. Long gone are the stock leaf springs, sent to the recycler for lunch money and swapped out for this full-tilt torque arm suspension from TCI Engineering. It’s largely designed as a bolt-on kit, aside from the axle brackets, but we went ahead and welded everything in as this would be a permanent change to the vehicle.

11. With the suspension under the car, we could temporarily set ride height. We will be revisiting this once we have received our new wheel and tire package and complete some body mods.

12. If you’re going to raise the power level of your engine, you need to raise the braking capability to compensate for the increased speeds you’ll likely experience. We called on Wilwood for the braking system, and went with the company’s manually actuated four-wheel-disc setup. Since we’ll be equipping the Mustang with 18-inch-diameter wheels, we were able to employ Wilwood’s SL6R six-piston calipers with 14-inch rotors up front. The rear setup features 12.90-inch rotors with an integrated parking brake for use with a full-floating axle design.

13. One of the subtle body modifications we chose to make on the car was the elimination of the factory driprails. We don’t want to go hog wild with the changes, but rather just clean things up a bit. Gillis Performance Restorations showed us how it’s done.

14. Cutting the driprail off reveals two separate pieces of metal that were previously joined together. Brian Gillis at GPR carefully welded the seams back up and once the bodywork was complete, it was time for some epoxy primer. We really like the smooth look at the edge of the roof now.

15. Another early round of modifications made a few changes inside the car, where we ditched the stock low-back buckets for something with support for our heads as well as our sides. These leather-clad Corbeau seats were just the ticket, and with the Corbeau harnesses bolted to the Mustangs Plus four-point rollbar, we’ll stay nice and planted and be able to concentrate on driving rather than our driving position.