1971 Challenger - Xtreme Vertible
XV's '71 Challenger Redefines Grand Touring
From the March, 2008 issue of Mopar Muscle
By Scott Ross
Photography by Richard Prince
Remember the orange '70 Challenger that we brought you in last July's Mopar Muscle that combined 21st century technology with the E-Body's late-20th century style? The one that left you wondering how its builder could improve on it . . . or top it?
Well, XV Motorsports topped it with a drop-top Dodge based on one of the rarest Mopars ever made-the '71 Challenger convertible, of which fewer than 2,200 were made.
A collector, who already had potent machinery in his garage, such as a Hemi-powered Superbird, a V-code '70 GTX, and an M-code '69 Barracuda, as well as nearly a dozen examples of American muscle and world-class exotica, wanted something like them, but different. "He approached us and told us he wanted to do a convertible," says John Buscema, president of XV Motorsports. "I told him that we had a '71 Challenger. I showed him the body style, and he really liked it, so he had it built."
John says, "The '71's engine is a heavily worked, 600hp, 6.1-liter Hemi." A T-56 six-speed was upgraded with triple-cone synchronizers for higher-rpm shifts, and a dual-disc hydraulic clutch went in place but not without some significant fabrication. "To put that tranny in requires reworking the transmission tunnel to fit a T-56, so we had to fabricate a new transmission tunnel," John says. Out back, there's a 4.33-geared, 8-3/4-inch rearend that works great with the T-56. "The reason we were able to do that and still have it usable is because the final drive ratio on a Viper T-56 is around 0.50:1," he points out, while noting that first through fourth are geared 2.66, 1.78, 1.30, and 1.00. "You have two overdriven gears: fifth and sixth. fifth is 0.74 and sixth is 0.50, which is great. it's all close-ratio,so you can run a lot of gear in the back of the car."
You can also run a lot of tire in the car. There are big Michelin Pilot Sports at each corner (335/30YR18s in back and 275/35YR18s in front), wrapped around a set of 18-inch, Kinesis-forged, three-piece wheels. They fit thanks to a little fender-lip rolling and XV's own Level II suspension system. The XV suspension replaced the OEM torsion bars/rear leafs with hardware fabricated in-house. The '71's chassis features two aluminum A-arms, aluminum high-pressure monotube coilovers, and aluminum spindles on each side in front, with a power rack-and-pinion steering system, custom front antiroll bar, and adjustable bumpsteer kit-all surrounding an aluminum K-member that cradles the powertrain while adding strength and subtracting weight. In back, there's a three-link suspension that features billet aluminum lower links, an adjustable Panhard rod, and aluminum monotube coilovers, with a custom rear antiroll bar for good measure. And for another good measure, there's XV's Level II brake package, with 14-inch rotors and six-piston calipers in front and 13-inch rotors/dual-piston calipers in back.
XV's fabrication shop also made additional structural reinforcements that went into the Challenger's body. "If you're familiar with the chassis stiffening that we do, this car has an additional piece in it that we put on convertibles," John says. "There are four pieces that we put in the car for chassis stiffening. In the convertibles, there's a fifth piece that we use on the framerails in the back." They also made a set of billet/hydraulic aluminum hood hinges for this car, which will likely join XV's product line soon.
The interior got as much attention as the chassis, with a prototype center console containing an Alpine audio system, flanked by two custom-upholstered Recaro bucket seats. A complete custom gauge cluster, including a 200-mph speedometer and 10,000-rpm tach, replaced the stock pieces. blue leather covers the seats, doors, and side panels.
Here's the best seat in the...
Here's the best seat in the house-the leather Recaro bucket between the T-56's pistol-grip shifter and the gauge set with a 200-mph speedometer and 10,000-rpm tach.
XV Motorsports prototyped...
XV Motorsports prototyped this console for this particular build, and they'll offer it on their future creations. Gotta love those cupholders!
Here's one front corner of...
Here's one front corner of the '71's chassis. Check out the custom spindle, coilover, upper and lower A-arms, and steering rack-secrets to this car's amazing handling.
That's 600 hp worth of 6.1-liter...
That's 600 hp worth of 6.1-liter Hemi under the functional Shaker hood.
When you have huge brakes...
When you have huge brakes at each corner, you need serious hardware throughout the braking system, as this master cylinder/Hydroboost power brake booster attests.
A show-quality blue paint job and a top-quality canvas convertible top were the finishing touches added before the '71 was unveiled to its patron. With more than a little understatement, John describes the customer's reaction to his newly built car: "He thought it was awesome!"
This build didn't take half of forever as some one-off and custom builds can. Ordered in January 2007, the car was completed the following June. What's even better, XV Motorsports can build an E-Body Mopar for you, one loaded with performance items from XV's long list of available features. John explains: "The way it works is, we'll sit down with the customer, get an idea of what they want, then we go back to them with a proposal and specs, laying it out, and refining it from there." That also includes providing paint chips of the colors they can use. If you're looking to DIY a Challenger XV of your own, they can supply the individual parts and subassemblies, too. If you want to see what else they can put on one for you, log on to xvmotorsports.com, and start your planning/dreaming there.
In the meantime, this '71 Challenger's not only graced one devoted enthusiast's garage and the roads near his home, it's also attracted positive attention to XV Motorsports, with a featured place on the company's web site following its completion. "I have another one just like it sold," John says with pride.
A little traveling music,...
A little traveling music, Maestro. Turn the key, fire it up, and awaaaay we go!
The front antiroll bar is...
The front antiroll bar is a NASCAR-style, splined shaft with aluminum arms and a custom billet mount.
How about these billet-and-hydraulic...
How about these billet-and-hydraulic hood hinges?
'71 Dodge Challenger Convertible
Built by XV Motorsports
Mopar Power Engine: A 6.1-liter, 372ci Hemi, balanced/blueprinted, hand-assembled, and loaded with parts made by XV Motorsports, which includes all the stuff you didn't get for Christmas: XV's own single-plane intake with billet throttle body, fully ported/polished heads, performance camshaft, equal length headers, 3-inch stainless steel exhausts with H-pipe and stainless Magnaflow mufflers, and a custom-tuned engine management system good for 600 hp. Transmission: Viper-spec T-56 six-speed (with triple-cone synchros for proper high-rpm shifting), with dual-disc hydraulic clutch and pistol-grip shifter handle. Rearend: 8-3/4-inch rearend, with 4.33:1 rear gears that work great with the T-56's overdrive fifth and sixth gears.
Sure Grip Suspension: XV Motorsports' Level II suspension system replaced OEM torsion bar/leaf setup with a short/long arm, double A-arms/high-pressure aluminum monotube coilover front suspension, a three-link with aluminum monotube coilovers, and Panhard rod in back. One more thing: Custom-fabbed antiroll bars. Two more things: Custom aluminum front spindles. Brakes: If just enough (i.e., stock Mopar brakes) are good, a lot more is even better. The 14-inch rotors and six-piston calipers stop the front, while 13-inch rotors and dual-piston calipers are on duty in back. Wheels: Now, these are "New York Giants!" wheels are forged three-piece Kinesis rims, 18x9-1/2 inches in front; 18x12s in back. Tires: Michelin Pilot Sports, 275/35YR18 in front, 335/30YR18 in back.
High Impact Body: A rare one (one of less than 2,200 '71 Challenger convertibles built) treated to remedial metalwork and paint prep by XV Motorsports. They also added structural reinforcements to keep the roofless steel body from pretzelizing when the go-pedal is mashed to the floor. Body features include a Shaker hood and billet/hydraulic hood hinges. Paint: Bright blue, sprayed on by XV Motorsports. Remedial bodywork and paint preparation also done by XV Motorsports. Interior: Recaro bucket seats flank an XV-made console that houses an Alpine sound system, Pistol-Grip shifter, and dual cupholders. XV also did the custom steering wheel. the custom gauge set includes a 200-mph speedometer and 10,000-rpm tach. Seats and side panels upholstered in leather complement the Challenger's body color.