1969 Ford Mustang Boss 429 Restoration - Raising The Restoration Bar

Correct or restored parts duplicating factory workmanship earn their stripes. Perkins photographed the markings for reproduction in this restoration. The “982” code is common for the 3.91:1 rear axle. Perkins replaced the original exhaust system (due to surface rust) with N.O.S. The muffler has the same 3-69 date code as the original to this Boss 429.

For decades, Perkins has been restoring the machined look to the rear axle “chunk.” Over the years, this bare metal develops surface rust on driver Mustangs. Rear axle housings frequently have runs in the semi-gloss black paint. The yoke (top) is unpainted. The pinion nut is daubed with yellow paint. The outside of the centersection is red epoxy primer (tinted Ditzler DP-74) with a shiny, machined surface and features heat-treated bolts tightened with zinc dichromate plated nuts backed by copper washers for sealing.

This photo reveals the color rings around the driveshaft and the overspray patterns of Raven Black paint, gray primer, and small amounts of sound deadener. Application of the body color forms an overspray pattern on the floorpan, although black against gray is not a high contrast.

The factory transmission crossmember is bare metal and shows the black weld lines for the attaching bracket. Most cars were exposed to the elements, so this crossmember becomes pitted.

Factory workers wrapped the parking brake cables with this orange strap to prevent interference with the moving assembly line. Perkins has seen maybe a half-dozen of these on cars in his career. He calls this strap “a nice little detail” on Steine’s Boss 429. The red dye on the parking brake cable clip is another trick detail, as well as the drip marks in the floorpan paint (top of picture). These drips are original and formed from paint runs when the body was baked at the factory.

Perkins took care not to disturb the original sound deadener, seen here in the passenger side inner fenderwell exhibiting its factory “textured” appearance. He sprayed the coil springs with orange paint, specific to the Boss 429, with the paint over-sprayed to the inside of the coil spring. The white paint on the bottom of the spring is a brush stroke.

Inside the passenger side front wheel well, the factory taped the original build sheet in this odd position, suggesting assembly line workers were in a hurry.

A new development in restoration is lightly machining bare steel surfaces to make them shiny, like when new. For example, notice the shine on the inside of the front brake calipers. Perkins takes off just enough metal to restore the shiny appearance to the raw metal (without affecting fit) and show a “just machined” contrast to the surrounding darker cast pieces. Mustangs are loaded with bare machined surfaces—spindles, rotors, rear drums, rear axle housings, transmission cases, bellhousings, and others. A little oil on the part will prevent surface rust from forming.

The front end reveals a seldom seen detail—spot welds in the unpainted, bare metal of the front unit-body framerails. Almost every older Mustang has surface rust on bare metal under the car. Minor restoration to remove the rust smoothes these original spot welds. The front suspension finish is bare metal for the tie rod ends, drag link, Pitman arm, idler arm, rotors, strut rods, sway bar hardware, and ball joint ends of the control arm. A well-known factory procedure is the inner halves of the lower control arms are dipped (not sprayed) in black paint. Spindles are bare metal, but heat-treated steel, which gives them a darker gray look.

Over the years, enthusiasts have done their best to restore Boss 429 engines to OEM stock. This engine may just be the best of them all in terms of adhering to the factory procedure.

Another restoration trick that moves this Boss 429 closer to the appearance of a brand-new car is the machining of raw metal surfaces. For example, Perkins machined the flat inlet ports of the master cylinder to a factory shine.

Conventional glass beading cleans but dulls the finish of Boss 429 cast aluminum valve covers. Perkins restores these covers to the correct original finish, which is cast aluminum with machined surfaces. To correctly restore the covers, Perkins glass beads with ultra fine (#10) beads, then tumbles three to five minutes with ceramic media, then re-machines the machined surfaces with a Bridgeport milling machine.

Boss 429s came from the factory with a Kar Kraft assembly line upper radiator hose with the factory staple clamp. Very few Boss 429s can boast an N.O.S. hose from Kar Kraft, as seen here.

The anti-backfire canister is not a difficult smog item to find, but the gold-galvanized clamp is a tough N.O.S. assembly line part to locate. Perkins got this clamp out of a master pack of clamps from a stash of Kar Kraft parts he purchased from Bud Moore. The galvanizing gives the clamp a textured finish, in comparison to zinc dichromate clamps that are too shiny and smooth.

The spark plug wires are N.O.S., date-coded the second quarter of 1969 to fit the window of production for this June 1969 production Boss 429—KK1896.

Although they might appear to be generic tie straps from a parts store, these “Panduit” tie straps are OEM. Panduit supplied Dearborn assembly and Kar Kraft. These straps were also used throughout the car, like inside the trunk to secure the taillight harness.

Factory marks, such as this “ElTl” on the inner fender apron, are easy to reproduce. The secret is to have a car with enough of these marks visible to reproduce the code and the location. Perkins would never add such a mark if he had not already photographed and found it on the vehicle.

The engine oil cooler is another “saved” item in this restoration. The factory drip marks on the side of the cooler would be extremely difficult to save if a restorer had to bead-blast this part. A detail restorers almost always miss is restoring the cooler with bare metal on the threaded inlet at the top, just to the left of the nut. The factory submerged the oil cooler in a vat of special thin paint. To prevent paint from entering the cooler, they inserted a cap over the inlet and outlet. The cap also protected the threads from paint, thus the bare metal.

This Boss 429 still had the original engine lift hooks, seen here with the original lighter blue-green paint. Bob calls this paint “slop blue” because it was a vendor’s incorrect attempt at Ford Corporate Blue. An outside supplier painted and sold these hooks to Ford.

The factory hung the hoods in this slot and then sprayed the paint, causing some damage to the metal as well as an overspray pattern. This slot is another example of factory workmanship, replicated here.

The trunk has every trick part. Every ’69 came with a plastic bag with the temporary warranty card, owner’s manual, extra set of keys, and a manila folder with the license plate hardware. The ’69s also came with headlight aimers. This car has a letter from BF Goodrich addressed to the original owner. Sent in the early 1970s, it contained a sticker to apply to the space saver wheel. The threaded rod is what Dearborn assembly bolted through the floorpan and into the framerail to attach the car to the skid on the moving assembly line.

This is the infamous, and almost nonexistent, Boss 429 battery vent cap removal tool. Perkins has only seen three of these tools in Boss 429s. Because each vent cap is sealed with a foam gasket to prevent fumes from leaking into the trunk, the factory tightened the caps very well. This plastic tool was needed to remove the caps.

Perkins opened the passenger-side door to show the stamping marks in the metal on top of the rocker panels. Elite restorers look for these factory marks when they grade the quality of the paintjob, but very few people in the hobby know about stamping marks in paint.

Here are more factory stamping marks in the metal, appearing in the wall of the inner fender panel under the hood. If this metal is pitted and requires work, then sanding and priming will eliminate these factory marks in the metal.

Perkins saved this small drip mark in the paint on the inside bottom lip of the decklid. Apparently, Dearborn assembly applied more paint than was necessary in this corner and baked the drip in place. Removing the paint destroys this drip mark. Bob blended paint around this original drip. Painters can put runs and drips in the primer, but apparently they cannot bake them on to make them pop like they are factory original.

The factory covered the bottom of each rear quarter with primer, but very little Raven Black paint. Most shops would simply fully paint these quarters, oblivious to factory procedure, and if there is a question about authenticity pronounce their restoration better than original.

The interior is untouched. Low miles and good storage kept the black deluxe interior mint. Very few cars can boast a like-new interior after over 40 years.

To be able to say the original door data tag, KK sticker, and tire inflation decal have not been removed is important to a car like this. Luckily, the paint on the 7,000-mile original Boss 429 was in excellent condition on the inside edge of the driver’s door. Therefore, Bob could save this area. He blended the new paint into the bottom edge of the door.

The “P” inside the doorjamb was the best original sticker on the entire car. Had the paint been poor in this area, Perkins would have had to restore the metal and remove the paper sticker.

One point of controversy on ’69 fastbacks (not just Boss 429s) has been the screws in the molded rear seat armrests. The two visible screws at the front are panhead-style plated in zinc dichromate (a gold finish). The remainder of the screws in this panel are zinc-finish, oval head Phillips screws.

Bob Perkins’ rule of thumb on interior tags and stickers also applies to restoration color codes and various labels on the undercarriage as well as the engine bay. “Only put back on what came on the car or was standard on all production cars.” Every mark and paint code, sticker, and label is backed up with a photo for this car. For example, this manual choke warning tag is original and still attached to the inside edge of the console near the driver’s right knee. This sticker and others are historically accurate and part of a great restoration.