Steve Turner
Former Editor, 5.0 Mustang & Super Fords
April 4, 2007
Photos By: Dale Amy
What you may not know about the construction of the '07 Shelby GT 500--and all other Mustangs for that matter--is that these cars go down the same assembly line as the Mazda 6. Moreover, the cars don't go down the line in runs. Instead, Mustangs and Mazdas make their way down the line together at the Auto Alliance International assembly plant. The Shelby engines are assembled by a pair of assembly associates on the Romeo Engine Niche Line.

CLICK HERE TO SEE THE SHELBY GT500 BUILD FULL PHOTO GALLERY

CLICK HERE TO SEE THE SHELBY GT500 ENGINE BUILD FULL PHOTO GALLERY

Horse Sense: The latest Shelbys seem as though they're limited-production cars, and dealers aren't shy about charging more for them because of it. But when you consider that Ford plans to produce around 9,000 each year for two to three years, those numbers aren't small. Especially when the original line of Shelby Mustangs, which ended in 1970, only resulted in a total volume of 14,559 units, according to Ford.

By now it's been verbally beaten into you that the latest Mustangs are the best ever built. If you've driven any of the Mustangs leading up to the S197, it's hard to argue that the latest car is a fine example of the breed. You might wonder what makes them so good. Part of the reason is that the assembly of the cars was moved from the historic-thus ancient--Dearborn Assembly Plant to the state-of-the-art Auto Alliance International plant in Flat Rock, Michigan.

If you aren't familiar with AAI, as it's called, this plant operates as a joint venture between Ford and its longtime partner, Mazda. What that means is that the two companies not only share space and build cars in the same building, but they're also able to use the same assembly-line techniques, improving efficiency and quality. Add in robots and plenty of high-tech procedures, and you get an amazing car for an attainable price.

The engine assembly has long been performed at the Romeo Engine Assembly Plant in Romeo, Michigan. We thought it only natural that seeing an '07 Shelby GT 500 come to life would begin with the engine. If you're new to this scene, the engines from the cars formerly known as Mustang Cobras have been assembled on the Romeo Engine Niche Line inside the Romeo plant. This is where two-man teams assemble the engines we all lust after, and it's where we began our tour.

After watching a security video, our tour guide led us through the plant past football fields of Three-Valve cylinder heads whirring down the assembly line. We exited the building and crossed to an adjoining structure that acted as a storage area during the Romeo plant's previous life as a tractor assembly factory. As we entered the Niche Engine Assembly Line, we were greeted by a row of engine examples produced there--the Ford GT, the Terminator, '96-'98 Cobra, and, yes, the GT 500. It was like being granted access to the James Bond Q workshop. We were assigned to follow a couple of engine builders as they began creating a GT 500, engine first.

It was an awesome journey, one we suggest you take with us in the accompanying photos and captions. Suffice it to say, if you buy a GT 500, we think you'll be happy with the results.

The Romeo process begins with pallets of fresh cast-iron 5.4 blocks that have passed through an exhaustive inspection process, ensuring measurements are within spec and the surfaces are free of imperfections. Each team of builders gives the blocks a quick visual inspection. If you look closely, you can see they're identified as "Condor" blocks. During the GT 500's development dating back to when it was simply the next SVT Cobra, the project's internal code name was Condor; it wasn't just something we made up for our Cobra vs. GT 500 story ("Condor vs. Terminator," Feb. '07, p. 40).

No pressure washer and brake cleaner at Romeo--each 5.4 block and crank are thoroughly washed in this high-tech washing machine, which washes the parts, then quickly dries them under compressed air and vacuum. The crank rides in a protective fixture for the cleaning ride.

Each pair of assembly associates is married to the engine via fastidious record keeping of the entire process. The team we followed down the Niche Line was Gary Marston and Jeff Hamblin. Each block and pair of cylinder heads are coded, noted, and added to a database that follows the whole powertrain. Once at AAI--we'll get to that assembly plant in due time--the powertrain is attached to a Shelby VIN. The reason for all this tracking is to ensure quality, and if there's ever a quality issue, Ford can track it back to the engine builders. As you can imagine, there's a lot of pride on the Niche Line, so if there ever were a problem, the other teams might give the offenders a hard time. Peer pressure is a wonderful quality motivator.

After installing the drain plugs labeling the block, lubing the main bearings with Motorcraft 5W50, and installing the bearings, it's time to torque the main caps in place and secure the crankshaft. Most of the power torque wrenches on the Niche Line are electric, and they're tied into a computer program that ensures the fasteners receive the proper torque. If something isn't up to spec, the tool's power is turned off and the procedure must restart. The crank bolts are torqued from inside out in a preset pattern.

With the crank fasteners torqued, it was time to check crank endplay. Everything was up to spec. The dowels for the cross-bolts are installed in the block next, then the cross-bolts are screwed into place and torqued two at a time. In the two-man teams, one person often operates as runner, who gets the parts, and the other is a gunner, who does most of the wrenching. During our visit, Jeff was doing most of the torquing, and Greg was gathering parts.

If you've followed the modular engine family, you know that many of them have featured powdered-metal, cracked-cap rods. The rods and pistons in the '07 Shelby GT 500 are from Mahle and come preassembled and precracked. The rods are still one piece, and this apparatus separates the rod from its cap. Gary inspected each piston and rod for obvious flaws and installed the bearings. Each rod is numbered and marked with paint to ensure the rod and cap stay matched.

The machine automatically prelubes the rods, bearings, and ARP fasteners with 5W50.

After sliding in the pistons and installing the rod bolts, Jeff torqued each pair of rod bolts with the electric torque wrench. These wrenches are tied into the assembly line and sense if the proper torque has been applied. If everything goes as planned, a yellow light indicates that it's safe to move to the next station. If the red light comes on, the wrench immediately halts, and it's time to stop and check things out, possibly leading to the engine coming off the line for inspection. This is rare, but it's nice to know those quality controls are in place.

Next up is pressing in the water-pump cup plug. The design of this cavity and the pump used on the GT 500 are said to improve pump flow by 50 percent compared to the Terminator arrangement.

After installing the oil pump, windage tray, and oil-pump pickup, the cooling system is checked for leaks with pressurized air. Checking for leaks at this stage eliminates problems down the line when the oil is filled.

Even a non-Ford guy knows this engine takes on a special personality as Jeff bolts on the Four-Valve cylinder heads. They're also visually inspected before being lowered on the short-block. The heads are shared with the Ford GT 500 supercar, but the GT 500 engine uses unique head gaskets due to the dissimilar aluminum heads and iron block.

First, the secondary tensioners and chain guides go on, then the timing gear and chain sets are preassembled and installed as sets. Gary holds the crank in place with a torque wrench as Jeff torques the cam gears in place. As we had previously reported, the GT 500 shares cams with its Terminator predecessor.

As luck would have it, a dozen or so Ford GT service engines were scheduled to go down the Niche line while we were there. As such, we were able to compare the cam gears between the two engines.

The larger cam gear is from the Ford GT, where the Shelby uses a smaller cam gear, a revised timing cover, and revised cam covers to clear the Mustang shock towers.

Similar to the other critical fasteners, the flywheel and clutch bolts are installed with the automatic torque wrenches. Here, Gary double-checks the fasteners' torque with a standard torque wrench. The automated tools and the standard wrenches are periodically checked for accuracy.

We're getting closer. After checking the crankshaft endplay, the oil pan, the crank damper, and the oil cooler adapter go on the engine. The oil cavity is then air-checked for leaks.

Here's our favorite part: the protective blue cover comes off the intake ports, the intake gaskets go on, and the blower/intercooler assembly are lowered into place. This is followed by the coolant tubing, wiring, and throttle body.

With the plugs and coil packs in place, the Powered By SVT coil covers are put on and oil goes in the pan before the engine receives a final check.

In the early days of the Niche line, the assembly associates actually signed the plates that adorn the valve covers of these special engines. Eventually, efficiency and permanence dictated that the signatures be replicated and pressed into the plates prior to installation. So stamp the plate, ring the bell, and another great Niche Line engine is born.

The newly minted plate goes in a familiar and prominent spot on the driver-side cam cover. These plates are valuable apart from the engine, fetching upward of a $100 at online auction sites. Apparently, the car-show Melvins like to have an extra plate to go with their display paraphernalia.

This final engine inspection is no simple visual once-over, rather it's a computer-controlled dry-test stand that actually runs the engine without fuel. The engine is plugged into the stand, the injectors fire, the plugs fire, and the throttle body opens, all as if the engine were running. Meanwhile, the fuel system is checked for leaks using pressurized air, which shows leaks much easier than fluid would. Everything checked out fine on Jeff and Gary's engine. We knew it would.

Before the complete engine goes on a pallet for shipment to Auto Alliance International, it receives exhaust manifolds and EGR tubing. This is the only area on the line that uses air ratchets, but the torque on the fasteners is checked again with a standard torque wrench before the engine is sent on its way.

Here are the proud assemblers of this GT 500 engine, Gary Marston and Jeff Hamblin. Being a member of the Niche Line team is prestigious duty at the plant, and you must have seniority and be on a waiting list to get a shot at the job. From there, new team members get about a month of training before they begin stamping their names on a plate.

After a morning of seeing our favorite modular engine born at the Romeo plant, we made the short drive over to Auto Alliance International to see the rest of the car come together. AAI is unique, not only because it's a joint effort between Ford and Mazda, but because most of the sheetmetal stamping is done right at the plant. Only the Mustang hoods are stamped off-site at a Ford stamping plant.

In a scene that could be from a Terminator movie, the sheetmetal parts are fork-lifted to the line where robots pick them up, hold them in place, and weld them together. Sparks fly and Mustangs are born. It's a sight to behold. This is one section of the plant where the Mustangs and Mazda 6s are separate, with only Mustangs welded together here.

After the welding is done, people take over to fit the hoods, doors, and trunk lids before the bodies go into the paint line. This is the first time we could distinguish the GT 500s from their Mustang brethren, but the paperwork that follows the cars ensures the workers and robots know the difference between a V-6, a GT, a Mazda 6, and a GT 500. It's an amazing feat of logistics and technology that allow this complex operation to produce cars with much greater quality than their predecessors.

Once the bodies are assembled, they're moved down an automated paint line to receive a few coats of Ford's finest. Then they move to the line for the subassemblies, wiring, and convertible tops, if so optioned. That paperwork hanging from the hood details the options. As this cradle moves down the line, it tilts to ease the installation of fuel and brake lines.

In an interesting step, the doors come off, which not only eases the installing parts into the cockpit, but allows for a narrower assembly line. Though the tolerances are much tighter on the latest Mustangs, Ford still pulls five bodies off the line each day to make sure the tolerances are within spec. By the way, those form-fitting fender covers are cool. Ford should sell those for the rest of us.

As we said, the doors come off the car, but they don't just lie around. The doors go down their own assembly line where they receive speakers, wiring, glass, and other needed parts. More impressive yet, the doors rejoin the exact car they were removed from.

The coolest point on the assembly line is seeing most of the drivetrain--engine, K-member, brakes, transmission, and rearend-installed simultaneously as they're hydraulically lifted into the chassis and bolted in. If only we could put our project cars together this fast.

Once the car is fully assembled, it goes through this rain room to ensure there are no leaks, then it runs on rollers while a worker views the car from underneath to ensure there are no exhaust or other leaks. Then it's off to the lot for shipping. In the case of GT 500s, they're then sent for striping, if it's ordered. During our visit in mid-December 2006, the striping was added at a nearby subcontractor. By the time you read this, the stripes will be applied at Auto Alliance International.

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