Mark Houlahan
Tech Editor, Mustang Monthly
August 2, 2012
Photos By: Steve Baur

Like most gearheads, Jeff Barfield loves to visit automotive websites and forums and read all about other people's project builds for ideas on his own project. Clicking away at links, bookmarking parts listings, build tips, and whatnot is a great way to spend an evening building your next project in your head. It was a late-model Mustang website that Jeff was visiting when one of the posts he came across was all about Factory Five Racing (FFR) and the company's Mk series Roadster, a replica of the iconic Shelby Cobra. So impressed was Jeff with the listed specs, he had to know more. He hit FFR's website, ordered the info pack and DVD, and visited the owner's forum at While waiting for the info pack to hit his mailbox, he joined the FFR owner's forum (there's now an official FFR forum, too, at and spent time checking out other owners' builds, asking questions, and even checking out other replica manufacturers. However, Jeff kept coming back to FFR. "I was sold on the FFR's very strong frame and light weight, and this would be the basis for my super-high-powered rocket," Jeff exclaimed.

You see, Jeff is a registered respiratory therapist and knows a thing or two about breathing, with both the human body and the four-stroke engine. Jeff wanted big-breathing and needed to move a lot of air to make the horsepower he was considering. First thoughts went to a supercharger of some sort, but after reading complaints of exhaust noise from the short side pipe-style exhaust (subjective some might say), Jeff opted to go the turbo route, saying, "I changed my build plan to include a turbo to act as a third muffler and help quiet the car down."

After much research, Jeff picked a Borg Warner T6 83mm turbo for his build and called upon AD Performance in Redmond, Washington, to build the stout short-block as a basis for his power-hungry build plan. The 408-inch Windsor is based on Dart's Iron Eagle block, and is stuffed with an Eagle forged reciprocating assembly, CP pistons, and a custom turbo-friendly Comp Cams hydraulic roller. Jeff finished the rest of the engine himself with AFR 225 heads, Edelbrock/Wilson/Accufab induction parts, and a Big Stuff 3 EFI system forcing the fuel through 120-lb/hr injectors.

Knowing the engine was going to be putting serious power to the ground, and considering the fact that he wanted to row his own with a five-speed in the tunnel, Jeff called upon the crew at Modular Mustang Racing (MMR) for one of the company's highly modified Tremec TKO-600 gearboxes. MMR's Pro Trans 900 features special heat-treated gears; as well as heat-treated input and output shafts; deburring of the gears for improved shifting, more efficiency, and less noise; plus a few other proprietary upgrades to allow 900hp capabilities. Backing the modified Tremec is a McLeod Street Twin clutch and aluminum flywheel, which feeds a DTS–built fully welded 8.8-inch late-model Mustang axle housing stuffed with an Eaton posi, 3.08 gears, 31-spline axles, and topped with a billet girdle cover.

With the whole drivetrain worked out, the remainder of the FFR's build was fairly typical of building one of these replicas; assemble the suspension and brakes, wire the chassis, and send the body off for paint. Jeff knew the wiring portion was going to be a nail biter (as it is for many builders), and enlisted the help of his father, Herschel, to help with routing the wiring and making sure the Auto Meter gauges, audio system, EFI wiring, and more were all correct. Herschel even helped with the brake system install as well. It was during one of these father/son build sessions in the garage that Jeff's father compared the size of the Roadster sitting next to the fully dressed 408 Windsor and T6 83mm turbo setup that was going to be shoe-horned into it and stated, "Son, this is just plain overkill. It is not needed for this little car." From that point on, Jeff and his family have referred to the project (and now the completed car) as "Overkill".

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Trying to find a painter for one of these replicas is a tough job. Many shops today turn away project cars and complete paintjobs, as insurance "panel work" is faster turn around and makes them more money. Luckily, Jeff lives in Valdosta, Georgia, and is within driving distance of one of the top FFR painters on the East Coast, Jeff Whitby at Whitby's Motorcars in Greensboro, North Carolina. Like many builders, Jeff had a difficult time deciding on a color to paint the Roadster, changing his mind more than a dozen times. "On the day my wife, Abbie, and I took the body to Whitby's, I was still undecided on the color, so my wife decided on Titanium Silver with black stripes," Jeff told us. We think Abbie did a great job with the color choices!

With the body out of the garage and the rolling chassis coming along, Jeff turned his concentration to adding an intercooler and all of the turbo piping to keep the iconic side pipes in place on the Roadster. He wanted to keep the intercooler somewhat hidden to not ruin the classic body's lines, but also get enough air to be effective. The exhaust was another matter entirely. Using a massive 5-inch down pipe, Jeff had to figure out how to split it into two 3-inch pipes and route them cleanly through the body openings to mate up with the side pipes. Jeff did much of the welding and fab work with some help from Voigt's Sheet Metal in Valdosta.

Once the bodywork and paint had been finished, Jeff picked up the body from Whitby's and commenced final assembly, including fitting the kit's interior pieces, carpeting the trunk, and more. At first, Jeff ran into some driveability issues with the basic tune he had in the Big Stuff 3, so he called upon famed engine builder and racer, Steve Petty, to do a little dyno tuning. After about an hour and a half on the dyno, Petty had the Roadster purring and the tune he built had the car making 780 hp on pump gas. With 18.2 psi of boost and a mix of VP 109/93-octane in the tank, the dyno registered a whopping 924 hp and 986 lb-ft of torque!

Steve commented that with a little C-16 race gas and more boost Jeff would surely be knocking on 1,100 hp. Jeff has recently installed a larger custom-made K&N filter and upped the boost to 24.6 psi with the VP C-16 Steve suggested. He took it for a ride, but has not had the car back to the dyno to verify the numbers. "After that ride, I got out of the car shaking. I finally found my limit," Jeff commented.