Some enthusiasts take the dictum “too much power is never enough” a bit too literally. Aftermarket sports-car tuners are all familiar with these guys. They’re the ones who call on the phone, ask how much of a power increase the tuner offers, and on hearing this information, remark earnestly, “Is that all?”
John Hennessey doesn’t get many calls like that. Hennessey Motorsports, known as HMS for short, tweaks the Dodge Viper’s 400-plus-horsepower V-10s to 550 horsepower and beyond, which is usually enough to silence even the most obnoxious caller. Massaging Vipers for four years has earned Hennessey respect at Chrysler—he was allowed to buy one of the first Viper GTS coupes, the window sticker of which was autographed by, among others, Chrysler vice-chairman Bob Lutz and product-development executive VP Tom Gale. As you would expect, his new GTS didn’t remain stock for long.
Within four months, Hennessey had turned his $71,964 GTS into a $108,764 “Venom 550,” as he calls it. That figure includes other HMS parts, but $22,000 of it is devoted to the Venom 550 package, which strictly addresses power and takes six weeks to install in Hennessey’s Houston shop.
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The engine changes are as extensive as their price is expensive. The heads from the stock V-10 are ported and polished. The valvetrain is extensively modified, with stainless-steel valves and roller rocker arms, heavy-duty springs, hardened pushrods, and a cam shaft that provides higher lift and slightly less duration. A K&N air filter feeds larger-bore throttle bodies, which are fitted to the V-10's intake manifold, which is Extrude Honed, ported, and polished.
The V-10 exhales through a stainless-steel exhaust system consisting of tuned headers and three-inch mandrel-bent pipe with twin Dynamax mufflers. The sum of these changes is 550 horsepower at 5700 rpm and 577 pound-feet of torque at 4500 rpm, which Hennessey will verify for the buyer on his Dynojet dynamometer.
Hennessey’s GTS lays waste to previous impressions of what constitutes “fast” for a street car. Despite inevitable but time-eating wheelspin, the Venom 550 reaches 60 mph in only 3.8 seconds. Gathering up traction, it charges through the quarter-mile in l l.7 seconds at 126 mph, past 150 mph in 17.9 seconds, and past 170 mph in 25.4 seconds. That’s just 3.4 seconds behind our fearsome 603-horsepower Lingenfelter Corvette’s 170-mph time, and it beat a Ferrari F50’s time by 1.4 seconds. With our right foot in it at the Transportation Research Center in Ohio, the Venom 550 tops out at a scorching 197 mph, 20 mph more than the stock GTS.
Our Venom 550 came with other HMS extras. The stock tires were mounted to a $3200 set of sharp HMS/Speedline wheels. A front-brake upgrade for $4500 included Alcon calipers and 13.5-inch rotors that Hennessey claims are more fade-resistant than the stock brakes. They didn’t fade at all during our tests, unlike stock brakes, which will soften with hard use.
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No rolling HMS catalog would be complete without the $5500 Connolly-leather interior our car had. We would have passed, though, on the HMS “short
springs” for $800. They quicken handling response and reduce understeer, but at what we consider an unacceptable cost to the GTS’s supple ride. We’ll take the $800 HMS/RT shifter, though, which tightens up throws significantly on the Viper’s gearbox at no cost to shifting speed and marginal cost to effort.
The Venom 550 is very loud. At 1500 rpm (about 70 mph in sixth gear), the interior booms with a mind-numbing resonance, and at 3000 rpm, the floorboards vibrate in agreement. The payoff, high on the tach at full throttle, is the most glorious ear-splitting wail this side of a locomotive whistle. This wailing is as impressive outside the car as it is inside, and it will alert everyone within a quarter-mile-including other drivers, folks enjoying a quiet evening at home, and insomniac grannies who will reach for that bedside phone to inform the fuzz some jerk is engaged in an egregious display of lascivious lawbreaking. Subtle this car is not.
Hennessey will build you a Venom 550 with the quieter factory exhaust, but its back pressure will cost you a dear 30 horsepower, making for a paltry total of 520.
Is that all? What kind of operation are you guys running, anyway?
Specifications
Specifications
1997 Hennessey Venom 550GTS
Vehicle Type: front-engine, rear-wheel-drive, 2-passenger, 2-door hatchback
PRICE
Base/As Tested: $108,764/$93,964
ENGINE
pushrod 20-valve V-10, aluminum block and heads, port and direct fuel injection
Displacement: 488 in3, 7990 cm3
Power: 550 bhp @ 5700 rpm
Torque: 577 lb-ft @ 4500 rpm
TRANSMISSION
6-speed manual
DIMENSIONS
Wheelbase: 96.2 in
Length: 176.7 in
Curb Weight: 3386 lb
C/D TEST RESULTS
60 mph: 3.8 sec
100 mph: 7.7 sec
1/4-Mile: 11.7 sec @ 126 mph
130 mph: 12.3 sec
150 mph: 17.9 sec
170 mph: 25.4 sec
Rolling Start, 5–60 mph: 4.2 sec
Top Speed (drag ltd): 197 mph
Braking, 70–0 mph: 166 ft
Roadholding, 300-ft Skidpad: 0.95 g
C/D FUEL ECONOMY
Observed: 13 mpg
EPA FUEL ECONOMY
City: 13 mpg