KJ Jones Senior Technical Editor
December 1, 2005
Photos By: Courtesy of Ford Motor Company, KJ Jones, From The 5.0&SF Archives

The year was 1979. While Pope John Paul II's visit to the United States introduced car nuts like us to the bubble-domed contraption that became known as the "Popemobile," a bigger automotive breakthrough was introduced by Ford Motor Company; the Fox-chassis Mustang rolled off the assembly line at Dearborn. The new Mustang was Ford's attempt to revive Mustang, since Mustang II, the econo-version of the ponycar, failed miserably with enthusiasts during its mid-'70s run.

Today, despite the huge popularity of the latest-generation '05 Mustang, the '79-'93, better yet, '86-'93, fuel-injected 'Stangs, still have a strong presence on the street, track, and at the shows. So enthusiasts new to the game are buying the early cars (can you believe a Fox can now be considered an "early" Mustang?) because of their availability and still reasonable prices.

There's no way we can stop progress and we acknowledge that the '05 Mustang certainly deserves the high praise and aftermarket attention it's been getting from everywhere since it debuted. But we think it's important to take a retrospective look at the venerable Fox 'Stang, and point out some of the plusses that make it a great platform for new and veteran enthusiasts to personalize and modify at fairly modest expense.

It's not that we can't find anything notable about the true old-school Fox cars ('79-'86); but when you look at things from a "best" perspective, these Mustangs really came into their own in 1989. By this time, all of the bugs had been worked out and Mustang's two trim levels (LX and GT) had firmly established their identities. From a mechanical standpoint, '89 marked the introduction of the mass air fuel-injection system for the masses-all 5.0 Mustangs. Mass air was initially equipped on '88 California cars only.

With mass air metering, driveability improved, as did emissions and fuel economy. But that's not all. Mass air proved to be a lot more flexible to performance upgrades than its speed-density predecessor. Basically, the mass air EEC IV processor was better able to adapt to the modifications that were becoming popular-intake manifold and exhaust header replacements, bigger throttle bodies, camshaft and rocker-arm ratio upgrades, and, of course, nitrous oxide and small supercharger systems.

On the whole, the '89-'92 Mustang era could qualify as being the best for engine-mod potential because the 302 blocks were stronger, the aforementioned mass air system handled the metering requirements much better than the speed density system, the E7TE truck cylinder heads were very good and standard on 5.0s, and the engines featured durable, forged pistons (power-adder friendly) as opposed to the cast, hypereutectic slugs of earlier and later H.O. 302s. Plus, the '89-'92 'Stangs had horsepower rated at 225, which was 25 more than the Fox cars ever had in prior years. Finding a stocker from this period (yes, a few are still out there) would be an excellent starting point for a Mustang newbie. (Note: The California-only mass air system is year specific to '88. Mass air sensors from later-year Mustangs cannot be connected to the '88 system without first modifying the mass air wiring harness and connector on the vehicle.)

The most important thing to consider after you've decided to modify a Fox Mustang is the direction in which you want to take the car. The Fox is a versatile creature. The cars across all years ('79-'93 and the Fox-4/SN-95 '94-'98 Mustangs) make for really good street cruisers, autocross, and road-race runners; and, as many of us who follow the all-Ford drag-racing sanctions already know, Fox 'Stangs can be some of the most exciting, heads-up drag cars we've ever seen. The possibilities for modifying Fox Mustangs are somewhat endless. However, we're going to take a look at three of the popular setups-street, autocross, and drag race-and give you our choices on which Fox is the "best" for each style. [Fox stops at '93 as far as I'm concerned, but KJ wanted to go Fox-y, so send him those flaming e-mails!-Ed.]

Street 'StangsAny '87-'93 Mustangs would fall under the "global" blanket for this category, but we consider the '91-'92 LX hatchback perfect fodder for a good, modified, street-driven Mustang. While the cars were equipped with airbags as a standard feature and a non-tilt steering column (additions/changes that were incorporated in 1990 that some 'Stang fans frown upon), the '91-'92s basically had all of the mechanical "good stuff." This included 225 hp that had come to Mustangs through the years, and '92 was the first year LX Mustangs featured the popular 16x7-inch, Pony five-spoke wheels as standard.

Also in 1992, Ford upgraded the LX's appearance slightly by changing the body-molding and bumper-strip color from black to the actual body color. These Mustangs also featured the stronger (300 lb-ft of torque, as opposed to 265 lb-ft from '83-'89) T-5 manual transmissions that came about in 1990 and included a 3.35 First-gear ratio that improved the seat-of-the-pants, low-end torque sensation drivers experienced when blasting away from a light. Depending on condition, the cost could be next to nothing for one of these cars, and, believe it or not, absolute virgins are still out there.

On the SN-95 (Fox-4) front, the '94 GT would be our call as the car with the best potential, mainly because a '94 currently can be had for a relatively low price. It marked the first year for the new body style, and the SN-95 Mustangs were markedly stiffer and heavier than the OG Foxes. Many believe the stiffness of the Fox-4 is a plus when it comes to making changes for street cruising because the cars are quieter than their earlier brothers. While the '94-'95 Mustangs marked the swan song for the beloved 5.0 and pushrod motivation, horsepower for these cars was listed at a fairly weak 215.

If modular performance is more to your liking, stepping up to a '97 Cobra isn't a "bad" move; it's just going to cost a bit more than a Fox-4 GT. The Cobra offered a little more ride excitement, thanks to its aluminum, double-overhead camshaft engine that pumped out 305 hp.

With respect to modifying a '94 GT, '97 Cobra, or any SN-95-style Mustang for the street, the good thing is they're easy enough to hop up. While it didn't happen right away, the aftermarket did develop a wide variety of performance and appearance parts for these cars, so the sky is pretty much the limit.

Straight-Line PerformersThanks to the popularity of the all-Ford drag racing sanctions and spectacular annual events like World Ford Challenge, Mustangs of any vintage and pedigree will always have a "life" in drag racing, if nowhere else.

However, the Fox most drag racers prefer to modify is the coupe, or trunk/notchback Mustang, primarily because of weight. The coupes were the lightest 'Stangs out there, and, of course, one of the key elements in building a successful drag car is weight-or lack of it. A stripped-down, '85-'93 coupe is the Fox to look for if the dragstrip is the place you want to be. The bare-bones four-cylinder cars are the most popular choices, as many of them are devoid of power features such as door locks and windows, factory-deleted air conditioning, and several-hundred pounds of other equipment that were included on V-8 Mustangs.

"You can be in the 12s for just a few bucks, if you put the money in the right place," a racer told us, with regard to how easy it is to modify a fairly stock coupe for drag racing. The 12s are just a start. Fox coupes similar to the '91 shown here, owned and piloted by NMRA Super Street Outlaw racer Manny Buginga, run e.t.'s in the middle-7-second range, at speeds close to 200 mph. It takes more than just a few bucks to achieve that kind of radical performance.

Fox FindingA good Fox can oftentimes be found hiding in plain sight-like on your street or in the grocery-store parking lot-with a "For Sale" sign in the windshield or marked somewhere on the glass. The local Recycler (www.recycler.com) or similar weekly auto-bargain newspaper and car shows are also great places to look for a '79-'98 'Stang, and to get ideas for mods you can do to your car. Prices vary from year to year, and a car's interior/exterior condition sometimes depends on its location, how it was driven, and how the owner took care of it.enough alone.

The UntouchablesSometimes it's just best to leave well enough alone and not modify a Mustang at all. Here's a list of a few Fox 'Stangs that came out swinging and delivered knockout blows the minute they were introduced. It's not that these cars can't be modified, of course they can. Because of their unique performance and appearance features (and, in some cases, their histories), we believe it's best to let the specialty Mustangs remain unchanged. But, who are we kidding? We're never able to leave well enough alone.

Where The Parts AreA wealth of aftermarket parts have been created for Fox 5.0 and 4.6 Mustangs, and modifying one of these cars from top to bottom can be as easy as your wallet permits. Mustang-specific classified sections, like the one on the NMRA's Web site (www.nmraracing.com), are awesome sources for locating parts that can be used to better your Fox. Local swap meets and garage sales are also good resources for 'Stang parts.

Here's our take on what some of the best, across-the-board initial upgrades are for any Fox Mustang:MechanicalAluminum cylinder headsIntake manifoldMass air sensorThrottle bodyShort-tube headersCam and 1.6 or 1.7 roller rockersPower adder (usually nitrous or supercharger, but turbos are becoming a lot more popular for street Mustangs)3.73 gearsAluminum driveshaftTremec five-speed or Lentech AOD transmission

SuspensionLowering springsAntiroll barsSubframe connectorsStrut-tower braceBigger brakes/rear disc brakesTubular K-memberAdustable control armsWheels and tires

AppearanceCustom paint/graphicsCowl or air-induction hoodBody kits/front fascia and taillight swapsInterior swaps (seats, consoles, dash, panels, etc)SeatsAftermarket gaugesStereo