Tom Wilson
April 1, 2009
A 5.0 LX, the Fox of Foxes. In '88 when this one posed on its 10-spokes the "aero" front end was still looking a bit new, but with previewing on the Thunderbird and Taurus the profile was not overly forced. In California, this car would already have been mass air; modifications were easy, cheap and nothing would change for six years.

The next year, 1987, saw more positive movement. Most obvious was the new "aero" front sheetmetal. Not as homogenous with the rest of the car as the original "four-eyed" front end, the aero look was modern and improved speed and economy; later it became the norm after sheer repetition. Inside the dash and instrument cluster was completely updated.

Underhood, the masked-valve head was gone, replaced by the storied E7TE casting from the '85 carbureted engine, plus a larger throttle body. Power was now 225 hp and 300 lb-ft of torque; a power level that would hold till the end of Fox Mustang production, no matter if Ford fiddled with the ratings at the end. Behind the 5.0 was the slick-shifting Borg Warner T-5 five-speed, backed by the light, but rugged 8.8-inch rear axle.

In fact, by 1987 the Fox Mustang had reached near completion. The next six years would see minor changes such as revised spindles, an occasionally deleted center console arm rest and replacing the unloved 85 mph speedometer. An air bag changed the steering wheel design in 1991, but in broad terms the Fox Mustang reached its final form in 1987 with one exception that would change everything.

To many this '86 Fox could be the best looking of the breed. The hood scoops and Cobra stickers were gone by then, leaving the purest expression of the original four-eyed headlight design. Mechanically, however, the masked-valve heads and inscrutable EEC-IV engine management made many think the world had ended a second time. Most curiously, the coupes were shunned by performance buyers then but are prized today. Tastes do change.

That change was mass air metering. If there ever was a single more important technical advance in Mustang history we can't recall it. Introduced on 1988 California 5.0s and made standard on 50-state cars the next year, mass air metering was the key to the electronic kingdom gate. Where the previous speed-density system could only be changed via the most sophisticated laboratory equipment-and it had to be modified when any meaningful hot rodding was performed-mass air automatically accepted changes in the engine's mechanical state of tune. Furthermore, Ford SVO, via engineer Hank Dertain, bundled the mass air mechanicals into a retrofit kit, allowing all EEC-IV 5.0 owners the freedom to modify their cars.

And it was this ability to modify the Fox Mustang that was such a huge factor in putting it over the top. That's good, as on the showroom floor the Fox Mustang was falling behind technically by 1989 when mass air was standard across the line. While the engines were durable and torquey, they lacked top end breathing (showroom stock racers shifted their 5.0's at just 4800 rpm for best lap times, for example). The rear drum brakes were easy pickings for critics, while the econobox 10-inch front discs were the real culprit and four-lug wheel attachment meant there was no inexpensive upgrade. The featherweight chassis proved about as rigid as cooked spaghetti, and drag racers found the rear suspension would tear out of the unibody when launched hard. Road racers figured out that same four-link rear suspension geometry was near schizophrenic, and in short, the 5.0 HO was considered a crude piece by many. The mainstream automotive press labeled it a cheap thrill and asked for refinement.

Compare this '93 GT with the '91 GT and there's no difference. This was both a blessing and a curse, but by 1993 it was time to update the aging Fox. Sales exhaustion was settling in, and the Mustang had lost its status as a tier-one car; that is, performance enthusiasts were still interested, but mainstream America wanted more refinement than the Fox could deliver.

Such shortcomings would normally be disqualifying weaknesses, but in the Fox 5.0 they weren't because by the late '80s the Fox Mustang had an additional trump card up its fender. Already 10 years old and simple as a country bumpkin, the Fox Mustang was fully amortized in Ford's accounting and could be sold dirt-cheap. Well into the '90s dealers routinely handed over 5.0 LXs for $14,000 and change; the lowest figure we heard for a new 5.0 LX in the early '90s was just under $13,000, an anomaly for sure, but it underlines the point.

This combination of low cost and easy modification was the Foxes' ultimate strength. By '90 nothing else came close in bang for the buck, and when Ford Motorsport SVO (now Ford Racing) and the aftermarket started bringing heavy duty and racing pieces to market the 5.0 was unstoppable. From 1990 on, enthusiasts looked at the 5.0 the same way we did; it was the best 7/8s finished car ever. You drove it home and finished it the way you wanted it. So if the Fox could be driven off the showroom floor as-is and deliver a ton of fun, fitted with an ever-growing list of speed parts it positively ruled.