1971 Dodge Challenger Convertible Viper V10 - The Full Monty

Building performance takes on many forms. Some people prefer the stealth approach, maintaining a stock appearance while hiding aces under the table, so to speak. Others look for overkill, making the world take notice as engines and accessories protrude from various parts of the body. For Tom Brown, it's sort of the best of both worlds. Other than rims and interior, his '71 Dodge Challenger maintains a fairly sedate outward appearance. When the hood is raised, there are 488 cubes of late-model Viper V-10 wedged into the engine bay, which is more than enough to send the machine deep into triple digit speeds.

Tom is no stranger to performance-modified cars-the Bloomfield Hills, Michigan-based roofing contractor has owned everything from big-block Vettes to a WO '67 Super Stocker. The idea behind the Challenger was to create a great-looking streetable driver, one that could get down when needed, but could go the distance (in this case, the distance of the 2005 Power Tour run from Milwaukee, Wisconsin, to Kissimee, Florida). The starting point for the project was two-fold: a 318-powered '71 Challenger drop-top that Tom had bought in 2001 and an insurance-totalled Dodge Viper.

The work on the program was given to Dr. Earl Brown, who happens to be quite the car artisan and, though not related, is Tom's long-time car builder. Believe it or not, the paint on this car is ten years old. The good doc added 3x2 channeled box tubing in the rear to give the convertible rigidity. The K-frame was built with 151/48-inch round tubing and still supports the factory-type suspension. The torsion bar suspension and factory quick-ratio steering was left in place, but the front-end was upgraded with KYB gas-filled shocks and Baer 12-inch disc brakes. Out back, the Dodge got the same brakes, plus custom ladder bars and coilover Strange shocks. All four corners ride on Momo 17-inch rims shod in BFGoodrich T/A tires that were, surprisingly, a swap meet find already chrome plated and ready to mount up.

The interior is far from stock. using the donor Viper, Carl's Interiors gets credit for the plush leather and Ultrasuede coverings, done in a conservative grey with Viper logos. The '71 seats were rebuilt and reinforced, the door panels were custom formed, and twin speakers are located along the lower back. The dash panel itself is no longer anything like 1971; it is a 21st century combination of highly visible gauge faces from the Viper. the biggest challenge was wiring up the gauges, including the custom interface using the vehicle speed sensors to make the speedo register accurately. Rounding it out is a Viper steering wheel and a custom model shifter with six forward positions etched in the knob.

Of course, it's what's under the hood that counts. The car was taken apart and the big V-10 was manipulated into the engine bay. The engine was not worked up since the factory's 500 horses would be more than enough to get the Challenger in motion. The firewall and trans-tunnel had to be raised 111/42 inches for clearance reasons, and the radiator moved up three inches, with that handwork covered by a neat air shield above the radiator. This, however, left no room for the stock hood latch, so those hood pins on this thing really are doing their job.

One of the biggest requirements when using late-model technology is adapting the peripheral computers to the project; in this case, the black box ended up in the driver-side kick panel along with the relays required. Earl Brown gets credit for that. Tim Spencer was also involved in the fabrication end of the project, and Ernie Miyamoto welded up the custom exhaust.

Behind the engine is a Tremec six-speed, perhaps the most popular of the new-generation gearboxes. The use of this unit required the tunnel be raised and the shifter location changed to make it fit. The old school 8.75 SureGrip rear was left in place, complete with a 4.30 ring that lets the quick-winding engine get underway. Tom says making the Viper Challenger a reality took over 1,000-plus man-hours, and the cost...well, he didn't answer that question.

So, what did Tom Brown end up with, besides a great ride (with just 200 miles on it since completion), to take on the 2005 Power Tour? In addition to big smiles and this magazine story, the car averaged 20 mpg on the highway. Coupled with the convertible comfort, big horses, and curb appeal, this is one date we think anybody would take out on a summer evening.

Fast Facts
Owner: Tom Brown, Bloomfield Hills, MI
Car: '71 Dodge Challenger convertible
Builder: Earl Brown
Engine: 488-inch Dodge Viper V-10
Heads: Stock Viper
Camshaft: Stock Viper
Crankshaft: Stock Viper
Rods: Stock Viper
Pistons: Stock Viper
Induction: Stock, show detailed and painted
Headers: Custom built by Ernie Miyamoto
Trans: Six-speed Tremec
Differential: 831/44 with 4.30 gear
Wheels/Tires: Front: Momo 17-inch rims, BFGoodrich tires; Rear: Momo 17-inchrims, BFGoodrich tires
Paint: Tor-Red
Best Performance: Top end-"More than the convertible top can handle."