Vehicle Overview
Holley “My Ride” page for 1973 Mach 1
This is our 1973 Mach 1 Mustang. This Mach 1 started out as a fairly basic model. It had a 302 2v engine, backed up by a C4 automatic transmission, and a 2.79:1 open differential. Other than the automatic transmission the only other really significant option was its AM radio. Had it not been equipped with the auto tranny or radio this would have been a “stripped” Mach 1. In 1973 the Mach 1 did not come with the deluxe inner door panels, so this has the standard, flat door panels. The interior is Ginger. The exterior color was originally Saddle Bronze Metallic. In about 2006 or 2007 the prior owner had the car repainted using Valspar House Of Kolor “Sunset.” The Sunset paint is a Urethane translucent paint with very fine metallic flakes. The finish dances in the sunlight, and it never fails to attract attention and comments anywhere it goes.
The prior owner replaced the original 302 engine when the distributor shaft gear and dam drive gear got into a fight, and both gears lost. He decided that was excuse enough to replace the engine with something with a bit more beef. He opted to replace it with a 1994 Ford Truck 351W (not 351C), and had it built to a moderate street/strip level. The pistons are forged, but only 9.5:1 compression to handle the low octane alcohol free fuel we have in Upstate Western NY. The cam was called a 3/4 race cam, but I do not have the build sheet for the engine, so without pulling things apart I do not have the “real” specs. I know it is a hydraulic cam, but I do not know if it is a flat tappet or roller lifer design. The headers are Hooker Ceramic Competition long tube headers that fit very nicely. The mufflers had been FlowMasters, but I changed them to a more docile muffler to reduce the drone from the mufflers at highway speed. The intake manifold is an Edelbrock RPM Performer, topped with a Holley 750 CFM carburetor with vacuum secondaries. The ignition system is an MSD electronic ignition with an MSD distributor.
The rear axle gears were replaced with a 3.5:1 TractionLok unit before we purchased the vehicle. But, the tranny was a bone stock C4, and with an engine that had a dyno output of 360 horsepower I decided we ought to replace it with something beefier, or build the C4 into a nice high performance unit. I really did not want to go through the grief of moving to an AOD tranny, and I liked the lighter rotating mass of the C4 vs an FMX or C6 auto tranny. So, we had it rebuilt using all high performance parts, All planetary 4 pinion gear sets were replaced by 6 pinion gear sets. The valve body had already been replaced with a high performance unit, so we left that alone.
Although tempted to bump the performance of the engine, I have resisted. The 351W performs nicely as it is, and I figure if I want to do any real romping around we have two Shelby GT500s (1969 and 2020) I can use for that purpose. So, I ended up focusing on making the car more comfortable for driving. The first upgrade was adding a Classic Air air conditioning system (R134, of course). The kit included a new control head panel, which used electrically driven motors for the air door, and hot coolant diverter valve, as opposed to using vacuum like the original heater control system used. The system’s kit included all of the parts needed, and it works perfectly.
The original instrument panel had a speedometer and fuel gauge. Everything else was an idiot light. I opted to replace it with a Dakota VHX analog gauge instrument panel, with a carbon fiber exterior finish and a red illumination lighting schema. It really looks great.
After using the new Dakota instrument panel I could see the coolant temperature was running at 240 degrees when idling for more than a minute or so, or driving very slowly. But when I got up to 30 MPH the temperature would come down to about 200 degrees (192-195 degree thermostat). I looked at the cooling system and found the original small radiator had been replaced by a larger radiator, but the fan and fan shroud were still the ones used for the small, original radiator – hence the radiator was not getting enough cool air pulled through its fins to keep the engine cool at low speeds and prolonged idling. I ended up ordering a Champion three row aluminum radiator, matching aluminum shroud, and 2 electric fans with the needed thermal control switch and fan relay. It was an easy upgrade to perform, and now the engine runs at the 200 degree level all the time, unless it is really hot outside and we are using the air condition, and at that the temp is inly about 210-215 degrees. So, problem solved.
I did some other upgrades as well, to help modernize the Mach 1. I added an ACP full length center console. I used double sided tape to mount a 3 x 3 x 1 block of clear Acrylic onto the center vertical bezel, and attached a Garmin Drive 51 GPS display. I also added the optional Garmin wireless backup camera, and an LED taillight set with sequential flashers. The headlights are not Halogen units, which required a headlight relay kit. I used the headlight relay unit to turn the headlights and parking lights on automatically any time the engine is running, and the parking light current is used in the trunk to power the backup camera and sequential turn signal circuit boards. As for the center console, I replaced the ash tray with a fabricated Power Panel with two 12 volt outlets and a dual USB outlet, using switched power.
After all of the upgrades were performed the Mach 1 was really more fun than ever to drive. But, when we acquired it we knew it had a few small, typical rust areas. One such area was the hood. So, I replaced it with a hood with nor only the dual NACA (NASA) hood scoops, I also included a fully functional Ram Air kit. The trunk’s back panel, especially around the taillight pods, had some rust also. So, I purchased the back panel. We then took the Mach 1 to a restoration ship to have the few rust spots and trunk back panel repairs performed, along with any painting needed.
Do you see it coming? We didn’t… We had looked carefully at the condition of the Mach 1 before we purchased it, and thought we had accounted for all the rust. Nope, this vehicle, as it turns out, had spent its for 10 years in Virginia Beach, and was owned by a sailor who was at sea most of the time. So, it sat, largely undriven. And the salt air (moisture) got into some pretty deep and unusual areas that could not be seen until trim pieces began to get removed. We had pin holes under the bright metal trim around the rear window glass and the windshield. And under the trunk seal we had a lot of pin hole corrosion. We asked the owner of the shop to tear the Mach 1 down and see how bad the corrosion was in the hidden areas, and it was bad. A lot of small pin holes in all kinds of obscure areas. What to do… In early September, 2019, we decided to fully restore the Mach 1, as opposed to patching it up.
We could have asked to have the car patched up the best it could be, and pawned it off on a high school kid who would have destroyed it anyway. But, we had made a commitment to the prior owner, who had it 35 years and was only selling it due to severe illness. We were going to be excellent caretakers during “our turn” with his beloved Mach 1, and we decided to honor that commitment. I do not want to even hint at how costly that decision has been, but we made it with our eyes wide open, and knowing it was going to be a very expensive project (it has been). But, once the project tis done it is going to be one marvelous looking and performing 1973 Mach 1.
There is hardly a panel on the car that has not been replaced or repaired, other than the floor pan, which is in really good condition, and the roof. Wherever we could we kept the original metal, and had new metal spliced and welded where needed. No “Bondo” or other plastic fillers have been used. Seams were filled using old school leading, like used to be done at the factory when they were built. Multiple primer, base white, color, and clear coats of paint have been shot, with wet sanding between all coats. Rather than using a traditional white decal for the hood scoop “351 RAM AIR” call out characters, we used a stencil so the underlying Sunset Orange paint peeks through the Hot Rod Black Matte paint to display the call out. That effect looks really nice
The new paint used for the restoration is PPG Sunset Orange, just a slightly darker hue than the Valspar Sunset color. It is also a translucent, fine particle metallic color shot over a base white. We also decided to add a rear spoiler wing and rear window louver slats. The hood will be equipped with the Dzus chrome hood lock-downs as well. The vehicle already had a dealer installed front spoiler, It is going to be a really nice looking, fully decked out Mach 1 once done. The restoration began in early October, 2019, and is expected to be completed in late August, 2020.
Once we get the car back I will update the photo.
Updates
The following link has a video made from a series of progress photos during the 13 1/2 month long restoration”
https://youtu.be/y0MiVAFj_sQ
A walk-around video on its last day of the restoration project is on our YouTube channel at the following link:
https://youtu.be/_Fl0B-qmlLI
Transmission Update
About two years after acquiring the 1973 Mach 1 the C4 tranny began to slip badly during its 1st to 2nd gear upshift as Wide Open Throttle (WOT). Prior to the upshift slipping the tranny shifted very firmly on the 1-2 upshift at WOT, and both rear tires would bark rubber. Rather than rebuild the C4 again, I opted to swap it out for an AOD (four speed Automatic OverDrive) tranny from a later model year Ford.
We acquired a rebuild, and beefed up, AOD from Monster Transmission, and opted to get the version that provided a firmer upshift than factory stock. There was a problem with the assembly where the Shift Shaft retaining roll pin was replaced with a solid retaining pin that was staked into the case flush to the case surface. Thus it was not possible to remove the shift shaft retaining pin in order to install an upgraded, multi-position adjustable shift shaft and lever assembly.
I found a hollowed our flute reamer that was used to remove some of the case material surrounding the solid retaining pin, and was able to eventually install the new Lokar brand shift shaft and lever assembly. A correct roll pin style retaining pin was then installed, and the transmission was reassembled.
The factory specifies 30 – 35 PSI for the Throttle Valve (TV) line pressure with the tranny in neutral and a 0.275” thick adjustment block being used with the TV cable adjustment at the carburetor. At 35 PSI I found the upshifts occurred sooner than I wanted, and were a a little softer than expected. I made one readjustment to 37 SI, which improved the upshifts, but I wanted them occur still later with respect to road speed, and a bit firmer. So I readjusted the TV line pressure once more, to 39 PSI. That turned out to be a good setting as the 1-2, 2-3, and 3-4 upshifts now occurred at a higher road speed, and were nice and crisp without being excessively firm or harsh.
With the AOD there are a few things that happened, all positive. First, the engine RPM at 60 MPH with the 3.5:1 TractionLok rear axle gear set is now just under 2,000 RPM. Previously, with the AOD the engine RPM at 60 MPH was just under 3,000 RPM, which would get on my nerves after as little as 20 minutes of driving at highway speeds.
Next, with the 0.67:1 final drive ratio from the AOD, the top end speed of the vehicle has been restored, as opposed to being reduced with the 3.5:1 rear axle gears having replaced the original 2.79:1 rear axle gears. There are two reasons the top speed of the vehicle has bee restored. First, the AOD final output ratio allows the output shift RPM to increase at maximum RPM at top speed. Second, the engine has more horsepower and torque than a stock 351W, wo it has the power to overcome the air resistance at higher speeds, even with a relative high effective final drive ratio from the AOD.
Fourth, in theory the Mach 1 has an improved fuel mileage measure due to the impact of the OverDrive output shaft effective ratio. In 4th (OverDrive) gear the engine is working more easily in terms of RPM, thus saving how much fuel is consumed per mile travelled.
Finally, the AOD has helped to significantly reduce the droning of the powertrain at highway speeds, making it a far more pleasurable vehicle to drive, even at highway speeds.
Future Plans
There is hardly a panel on the car that has not been replaced or repaired, other than the floor pan, which is in really good condition, and the roof. Wherever we could we kept the original metal, and had new metal spliced and welded where needed. No “Bondo” or other plastic fillers have been used. Seams were filled using old school leading, like used to be done at the factory when they were built. Multiple primer, base white, color, and clear coats of paint have been shot, with wet sanding between all coats. Rather than using a traditional white decal for the hood scoop “351 RAM AIR” call out characters, we used a stencil so the underlying Sunset Orange paint peeks through the Hot Rod Black Matte paint to display the call out. That effect looks really nice. After the C4 tranny was replaced with an AOD, I felt that at long last the 1973 Mach 1 restomod project was finally completed.
The new paint used for the restoration is PPG Sunset Orange, just a slightly darker hue than the Valspar Sunset color. It is also a translucent, fine particle metallic color shot over a base white. We also decided to add a rear spoiler wing and rear window louver slats. The hood will be equipped with the Dzus chrome hood lock-downs as well. The vehicle already had a dealer installed front spoiler, It is going to be a really nice looking, fully decked out Mach 1 once done. The restoration began in early October, 2019, and is expected to be completed in late August, 2020.
Once we get the car back I will update the photo.
Comments
No one has left a comment yet.