Don Roy
November 1, 2006
Photos By: Jerry Heasley

As the original owner of this 1991 Mustang GT, Brian O'Quinn told us that the car has never let him down. While this is Brian's first Mustang, he is used to vehicles that perform. As a teenager, his first set of wheels rode on a 1972 F-100 pickup that packed 390 cubes worth of V8 under the hood. After he sold the truck to an uncle, Brian dallied with a 1984 Camaro for a while, but found the transmission a little weak. Well, several transmissions, actually. Then, one evening just at dusk, he first saw a black '91 GT sitting with only the parking lights on. He was smitten. When the car drove away, the rumble-song of its dual chambered Flows simply knocked him head over heels.

The GM was soon traded in on the Jet Black GT you see here and Brian hasn't looked back since. At first, their relationship was a little strained. Brian told us, "I learned to drive a standard the second I drove it off the lot. It was an interesting drive home." For the first few years, this GT was Brian's daily driver and, while it started slowly, the mod bug had bitten. Blame those mufflers. "I started with Flowmasters in '92, then the baffle, then a filter and, today, I'm on my third supercharger, second set of wheels and I've upgraded or replaced just about every single part on the car. It's been a great learning experience."

Through the decade and a half that they've been together, about 68,000 miles of Texas blacktop have passed beneath them. Other trucks have come and gone as Brian works to keep the mileage reasonable on the GT. One of the things that he hasn't changed, though, is the paint. "It has its share of nicks and tiny dents," Brian mentioned, but "it is the original paint from Ford and is often mistaken for a new paint job."

Growing Together
While Brian has a mechanical background, his familiarity with things automotive was sparse. The Mustang spurred him to learn more. "I knew nothing of Mustangs, but soon learned everything there was to know by reading books, magazines and watching friends working on their Mustangs. I read Ford catalogs from cover to cover to know what every single part was and what its function was. Before I knew it, I was installing a blower, headers, cam, heads and on and on." When he first took delivery, the GT's engine was putting out 190 RWHP. Today, that number has grown to almost 500 RWHP, thanks to the current supercharger, a Vortech S-Trim pumper.

Of course, the supercharger isn't the only component helping out this engine. It's one part in a chain of upgrades that include an E-303 cam, Edelbrock Performer heads, a GT40 intake and BBK 65mm throttle body. With the blower, fuel system changes were also called for and those included 42 lb/hr Ford fuel injectors, 255 lph worth of Walbro in-tank fuel pump, along with an Aeromotive fuel pressure regulator. Even with the boost set at a leisurely eight psi, normal Texas heat makes the use of an intercooler prudent.

Cartech Turbo from San Antonio whipped up a custom design at Brian's request and even drove from there to see him in Austin to provide customer support. If your Lone Star state geography isn't all it might be, that's a two and a half hour round trip. The 3-inch tubing on the intercooler ensures maximum flow with little restriction. Valve train upgrades, including Ford Mototsport 1.6 ratio roller rockers, have allowed the maximum RPMs to climb to 6800, while the Edelbrock heads boosted compression by a half-point to 9.5 to 1. In their own ways, each of these changes contribute to make the output power level what it is today.

Suspension
MAC rear control arms, upper and lower; SVT Cobra rear sway bar; KYB 5-way adjustable struts and shock absorbers; Ford Motorsport progressive rate springs; BBK caster/camber plates; Offset steering rack bushings, poly sway bar end link bushings

Wheels And Tires
Centerline Star 16 x 8-inch wheels with Dunlop 245/45R16 XP8000 radial tires

Over the years, Brian and his 'Baby' have developed a special bond. "I know when friends or family call, I normally would say 'I'm working on my car' and that's the truth... but it's not just that. The car acts as a getaway for me from the stresses in life and just eases my mind when I upgrade or replace something." In search of more power, those upgrades also included a set of BBK equal length, shorty headers coupled to their catted X-pipe, which then feeds into Baby's signature Flowmaster Series 40 mufflers. When you go through the list of modifications to the car, you might think that Brian has had a lot of stress in his life. Even if that's the case, it hasn't clouded his mind about what his Baby needs.

Permanent Bond
The classic lines of this car have only been slightly modified by the addition of a Saleen rear wing. Changes inside only reflect those critical to ensuring proper operation and the continued health of their venture. A pair of Auto Meter gauges, monitoring fuel and boost pressure, are the only notable changes from how the GT's interior looked when it rolled out of Dearborn. During one period in its life, there was a host of Alpine stereo equipment installed, including a head unit, equalizer, disc changer and epicenter. See, Brian was working at a local stereo installer at the time. Boston Acoustics speakers and Stillwater subwoofers did the job pumping out the results, but all that had to change. "Once the engine began getting louder than the stereo, I removed all the audio and stuffed a Kenwood CD player in the dash." Sounds like Brian's got his priorities right.

One of those priorities - and something that many in search of big power forget about - is suspension work. Stance is something important that defines the visual appeal of a modified car and this Baby has it in spades. In part, that's due to a set of Ford Motorsport variable rate springs and the Center Line Star rims that grace all four corners. KYB 5-way adjustable dampers all around and MAC upper and lower control arms out back help to make sure this Baby doesn't lose it's cool when things get bumpy.

To keep the power heading where it should, there is an upgraded T-5 manual transmission in place, courtesy of Pistole's Transmission in Austin, as well as an aluminum driveshaft and 3.73 rear axle gears obtained through Ford Motorsports. A Stage III clutch from S.P.E.C. handles the responsibility of connecting it all at the right time. Brian has done a lot of the work himself - even yanking the engine in his driveway a few times, including twice in one three-week period. Still, the development of his automotive skills didn't only come from reading books. Brian is an active member of Austin Area Stangs, where he is able to share his enthusiasm for all things Mustang. He is often able to help out other members with his current GMC Duramax Diesel pickup, towing or helping move bulky pieces. He sometimes is able to get help from them as well, for example, when he'd reached the end of his rope in tuning the engine.

Club members led Brian to Protech Performance in Austin to set up his AEM engine control unit. His original choice hadn't worked out well and he'd converted the control system from MAF-based to using a MAP (manifold absolute pressure) sensor. "I found that the car actually idled better, ran better, and even the time my blower belt had come apart I could still drive it NA with no problems." Still, there were other little bugs that needed sorting out. For example, his MSD distributor's output signal didn't work well with the AEM box. Switching back to a Ford OEM distributor fixed that issue. Ultimately, Protech got it sorted out, getting Brian into their shop within a few days and strapping the GT onto their dyno.

As far as future plans go, there's not much left to do on this GT. Still, Brian is looking to do the rear brake conversion to disks, so that he can match the 11-inch Power Slot rotors he's installed up front. He says his priority is, "to get the car to a point that I'm confident I can drive it any time I want and also go to the track whenever I want." Certainly, hot performance and subtle good looks make for a pretty Baby.

Specifications
Brian O'Quinn's 1991 GT

Engine
Ford 5-liter V8

Engine Modifications
Ford Motorsports E-303 camshaft, 1.6 Roller rocker arms, GT40 intake manifold, 42 lb. fuel injectors; Edelbrock Performer 5.0 aluminum cylinder heads; BBK 65mm throttle body, equal length shorty headers, 2.5-inch catted X-pipe; Flowmaster 40-Series 2-chamber mufflers; K&N air filter; Walbro 255 lph in-tank fuel pump; Aeromotive fuel pressure regulator; MSD Ignition coil, 6AL controller; Vortech S-Trim supercharger, 2.75-inch pulley; Cartech Turbo intercooler, 3-inch piping; Canton 8-quart oil pan with windage tray; ARP main bolts; FelPro head gaskets; Fluidyne aluminum radiator; Flex-A-Lite dual electric cooling fans; S.P.E.C. Stage III clutch; AEM 1400 ECU; Wideband O2 sensor; Converted from MAF (mass air flow) to MAP (manifold absolute pressure) intake sensing

Driveline
T-5 manual transmission, upgraded to Cobra Z specs; Steeda Tri-Ax shifter; Ford Motorsports aluminum driveshaft; 3.73:1 rear axle ratio

Numbers
Pump gas, 8 psi Boost: 480 WHP, 490 TQ

Interior / Exterior
Brian O'Quinn's 1991 GT

Chassis
Power Slot 11-inch front brake rotors

Exterior
Saleen rear wing

Interior
Auto Meter Ultra Lite gauges, including fuel pressure and boost pressure

Photo Gallery

View Photo Gallery