KJ Jones Senior Technical Editor
September 15, 2011

Sad Saddle Situation

Q I have an '89 GT convertible with seats that I'd like to have recovered using the same material and design. The problem is, I can't find anything that matches what I have.

The GT's seats are tan leather with black on the sides and the seams are red with "Mustang" written in the headrests. I've never seen a set similar to them before, and I don't know if they're special edition or aftermarket.

The seats match the rest of the car's interior, and the top is also tan with brass color on the side. I need all the help I can get.
Name Witheld
Via e-mail

A We're fairly sure you have a custom interior and ragtop in your GT. Unfortunately, there probably isn't an off-the-shelf, exact replacement you can purchase. If possible, ask the 'Stang's previous owner for information about where the seats were originally done, and call that company to see if it offers the replacement material. You could also ask if it would be possible to deliver the seats to them for the repairs.

If that doesn't work, contact Classic Automotive Interiors (a division of TMI Products), in Corona, California [(800) 624-7960; www.classicautomotiveinteriors.com]. The company specializes in replacement and restyled upholstery for Fox Mustangs, offering a wide variety of materials and patterns that allow you to restyle your Mustang your way.

If the Shoe Fits...

Q I currently run 28x10.5-15 Mickey Thompson ET drag slicks on my '91 LX coupe. The car still has a stock-length rear and axles, and it's not mini-tubbed. I've been thinking about trying a drag radial tire, but I don't know what size will be closest to my slicks using 15x10 Weld Alumastar wheels with 611/42-inch backspace. Thanks for your help.
Ron Adams
Baldwin, NY

A A 275/60-15 drag radial is already close in size to the 28x10.5-15s you're using with the 10-inch-wide wheels, so fitment on your 'Stang shouldn't be much of an issue, especially if you've given the stock wheelwells some attention with a sledgehammer. Actually, we've seen 'Stangs with jumbo 325/50-15 drag radials stuffed under their hindquarters, using the same-size wheels without mini-tubs. It can be done, but the bottom line is, it's all about how hard you swing that sledgehammer.

The "FI" Stays the Same

Q We have an '85 GT with CFI on it, and we're trying to choose between a four-barrel carb and a Speed-Density EFI system. I haven't seen any articles about converting from CFI to EFI. Is there an easy way to do this? I assume I need to take the wiring and computer out of a newer Mustang and transplant it, right?
Tom Saladin Jr.
Reed City, MI

A No disrespect to our carb-faithful readers or EFI Mustangs' EEC technology, but we think converting a 'Stang's engine management to one of the modern-day, Speed Density-style, fuel-injection systems that are available is your best move. The new PERFECT engine-management system by Painless Wiring (www.painlesswiring.com) or XFI by FAST (www.fuelairspark.com) are good products to try.

The PERFECT system is comprised of a custom fuel-injection harness that includes OEM connectors and a compact, waterproof PCM that has been fully programmed and dyno-tested for maximum horsepower, torque, and fuel economy with a stock 5.0 engine. It's an easy plug-and-play deal that requires no programming.

If you're going to modify your engine, XFI is a lot more versatile than stock-style engine-management equipment, and it offers a greater ability to tune any mild-to-wild engine/drivetrain/ power-adder combination you can think of. The system is also easy to understand and manipulate, so using XFI to set up your 'Stang for street use won't be a problem.

With either management setup, a good return-style fuel system and ignition box is also required. Aeromotive's (www.aeromotiveinc.com) Fox-Mustang fuel system is all-inclusive (fuel line, rails, pump, filters, regulator, and sumped tank) and is a hassle-free method of ensuring your engine has sufficient fuel. We suggest using an MSD (www.msdignition.com) Digital 6 box to handle the ignition chores.

You'll also need a good EFI intake manifold, fuel injectors, and other basic pieces to complete the conversion.

Ground Out

Q I just finished completely rewiring my '90 GT. The car is street driven on a regular basis and taken to the track for some grudge-night fun as well. I'm having trouble with the voltage now, and I hope you can help.

I mounted the battery in the hatch area and grounded it to the rear chassis. A 1-gauge wire was used to send the 12 volts forward-with a front ground wire from the chassis to the motor-to a solenoid on the left fender. I also installed a 130-amp alternator.

For some reason, voltage seems to drop when I have the fans, lights, and electric water pump on at the same time. I know that's a lot of accessories running all at once, but they're all necessary. I don't have the stereo blasting while I'm driving the car, but I'd like to be able to do that, too. Thanks!
Adam Symonson
Columbus, OH

A Hopefully you've seen our report on this subject in our May '07 issue ("Power to the Pony," p. 182). We had the same desires-a street-driveable 'Stang with full voltage and no electrical issues while multiple accessories are on, including the stereo, for our project '86 T-top coupe.

There's basically no way a 'Stang's chassis alone is capable of being an effective ground. We recommend you ditch your current ground setup and establish a heavy-gauge, dedicated ground wire for your Mustang that runs to one or a series of posts (floating grounds) up front in the engine compartment and the cockpit.

Tie all your critical electrical components into the ground point. By doing this, you will reduce the amount of offsetting voltage in the electrical system that's currently giving you grief. You should then see normal voltage readings (greater than 13.2) when you're cruising with your accessories running and the tunes playing-loudly, of course

Virgin Of The Month

Fox Hunting

Q I'm thinking about buying an '88-'93 5.0 Mustang. I've owned a '67 with a 428ci engine, a '70 Boss 302, and a '72 coupe with a 429ci engine in the past. I have minimal knowledge of what things the Fox Mustang of this age might have problems with, such as driveline, suspension, brakes, and so on. If I could get a general list of things to watch for, I would appreciate it.
Scott Blair
Via e-mail

A Here are a few thoughts from our good buddy, Sal Ybarra, on what to look for when you're Fox hunting. Sal has a knack for finding Foxes for sale that are in excellent shape-and virgin, in many cases-so we consider him somewhat of an unofficial authority on the subject.

The best cars are the unmolested ones. Things to look for that may have been changed or tampered with include the upper-to-lower intake-manifold brace on the rear of the intake and the air silencer. Make sure the heater core isn't bypassed at the firewall. You should also check the clutch fan for cracks, and make sure the serpentine belt is routed correctly and passes over the pulleys for all the accessories. A sticker on the core support articulates the routing for the belt.

While it's not a 100-percent-proven statistic, we've found most Fox-bodies that have been in accidents are usually hit in the front. Confirm all the belt-routing and air conditioning info stickers are affixed to the core support, and check for signs of wrinkles or deformities and unusual gaps on the inner-fenders and where the fenders mount. Another not-so-common item to check is the hood latch. If the sheetmetal where the hook catches the latch is beginning to peel back or is cracked, that particular 'Stang may be on its way to needing a cowl panel and windshield replaced, as it probably won't be too long before the hood you think is latched flies up and wreaks havoc while you're driving down the freeway. If you can inspect the Fox's undercarriage, look for deformed or cracked floorpans and torque box damage, which is common to most street-driven '79-'93 Mustangs.

If the car you're looking at is modified, make sure the products used are high-quality and the installation has been properly done. For example, 211/42-inch mufflers hastily welded onto the stock 211/44-inch exhaust system is wrong. A complete after-cat exhaust system or an X-shape crossover installed with solid welds shows the owner cared enough to spend the money to do it right, and that will show throughout the rest of the car.

According to Sal, the best-year Fox Mustangs are '91-'93, for a variety of reasons. First and foremost, '92-'93 'Stangs have the preferred front-suspension geometry, as well as color-matched body moldings and an integrated map/dome light, as opposed to the separate dome light and map light that swivels in older models. Mustangs in the '91-'93 year span are also equipped with a driver's airbag. If you're looking to install an aftermarket steering wheel, this can be a negative.

The '90 'Stangs have airbags too, but they apparently also have one of the worst issues: Their cork valve-cover gaskets are prone to leaks.