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Any parts missing?


Well-known member
Aug 2, 2005
Dallas, TX
Visually, it looks complete to me, but I don't own an Impala. It has the two pieces that connect to the MAF, the air filter, and whatever that other piece is, so I'd say yes (for what my opinion is worth).


Well-known member
Feb 18, 2002
Looks complete - the "sraight" pipe runs off the factory elbow from the throttle body. The round cap goes on top of that elbow.

The MAF sensor goes in line next, then to the metal elbow, down to the plate and then to the air filter below the body (sits in the cavity behind the fascia in front of the tirewell)

...in the meantime:

Callaway SuperNatural Impala SS; Chevrolet Impala customized by Callaway Cars; Evaluation by Don Sherman (Motor Trend, 5/96)

Highway champions aren't born; they must be crafted piece bypiece. At least, that's the accepted theory in the automotiveaftermarket, where the end of the factory's assembly line ismerely a starting point for greater things to come. A primeexample of this is the SuperNatural Impala SS by Callaway Cars inOld Lyme, Connecticut. Now in its final year of production,Chevrolet's big LT1-powered rear-drive Impala is a quick,entertaining ride for a select few customers who appreciateclassic American engineering served with plenty of elbowroom. Butfrom Reeves Callaway's perspective, Chevy's hulking sedan is aZ28 with a stretch wheelbase and surplus doors. In other words,the Impala SS is an excellent candidate for SuperNaturaltreatment. Callaway's SuperNatural technique is a fancy name for thesame sort of modifications that hot rodders have bestowed uponthe small-block Chevy V-8 for 40 years: reshaped combustionchambers, polished intake and exhaust ports, larger valves,wilder cam timing, and less-restrictive intake and exhaustplumbing. Of course, Callaway has added a few modern touches tothe process. Instead of tediously grinding and polishing criticalcylinder head surfaces by hand, the job is done in a $ 385,000automated milling machines. Custom software for the enginecontrol computer is another sophistication far beyond the meansof your average shade tree tuner. In addition to giving the engine deep breathing lessons,Callaway stretches piston displacement by means of a 0.030-inchoverbore and a forged crankshaft with a longer stroke. Forgedrods and pistons are loaded into the resulting 383-cubic-inch(6.3-liter) block to ensure longevity in the hands of thecriminally lead-footed. Each SuperNatural engine comes with a dyno sheet. The oneattached to our test car revealed a torque curve as flat asKansas and a horsepower plot that raced straight from just over200 horses at 2750 rpm to 404 horsepower at the 5750-rpm redline.Callaway's claim is a 50 percent power increase over a stock5.7-liter LT1 throughout the rev range. During the '60s, car manufacturers routinely sold lusty400-horsepower coupes and convertibles without fretting oversupport systems such as the suspension and brakes. Thankfullythat approach started to change about 20 years ago, when domesticauto makers began to recognize the importance of handling andstopping. To rein in the herd of horses under the Impala's hood,Callaway upgraded the front brake hardware to a full Brembosystem, which includes 13.1-inch vented and cross-drilled rotors,four-piston aluminum calipers, and Pagid metallic pads. (Thesebrakes were originally developed for use on the Ferrari F40.)Chassis modifications include four Koni adjustable shockabsorbers, Eibach coil springs that drop ride height a half-inchwhile stiffening wheel rates slightly, five-spoke Forgelinealuminum wheels, and big-boot BFGoodrich Comp T/A ZR.tires--275/40ZR17 in front and 315/35ZR17 in back. (The hot '96Corvette Grand Sport wears the exact same wheel and tire sizes.) No project car would be complete without a few cosmetictouches. To correct a factory oversight on the pre-'96 Impalas,there's a small VDO tachometer added to the instrument panel. Apair of molded carbon-fiber fuel-injector covers dress up theengine bay left naked by the installation of Callaway'slow-restriction "Honker" intake duct, which disposes of a largemolded-plastic resonance chamber. The final add-on is a flyingCallaway family crest badge on the hood to inform the curiousthat this is not your father's four-door. Actually, the I.D.badge is a mere detail because the SuperNatural SS machineradiates such excesses of bravado that whole neighborhoods go onred alert at the mere thump of its basso exhaust. Broadshoulders, nasty black paint, and fat-boy tires are prima facieevidence of evil intent. The initial tap of the throttle jolts the driver into a zestyframe of mind.Classic V-8 reverberations rumble through the2.5-inch stainless-steel exhaust system, but that doesn't fullyprepare the driver when throttle plates are cracked to explorethe SuperNatural dimension. Steering and braking responses are equally forthright. ThisImpala perfectly impersonates a Corvette in four-door clothing. Over minor road imperfections, the Koni shocks act as ifthey're frozen solid, so ride motions are occasionally jiggly andnervous feeling. That would ordinarily convert to dire harshnessover major bumps, but the Impala has a full frame to intercedebetween potholes and pants' eats, so the firm suspension settingswork just fine. When asked to veer from the straight and narrow, this carbreaks crisply with no discernible body roll. Pitched into ahigh-speed sweeper it responds with swift accuracy, despite(at,214.1 inches long) being only slightly smaller than manyislands of the Indonesian archipelago. The SuperNatural SS,however, demonstrated its best behavior when we wired our testequipment to it. It thundered out of the hole with wide reartires alight and clicked off two firm redline upshifts runningdown the quarter mile. The dash to 60 mph took only 5.9 seconds,1.4 seconds quicker than stock. The quarter-mile ticket reads14.0 seconds at 100.3 mph, beating the standard model by 1.6seconds and 10.2 mph. This Callaway-modified Chevy wriggled through the slalom withan agility that belies its two-ton-plus curb weight. The 63.6-mphaverage speed through the cones is 1.0 mph better than stock, butslippery leather seats, numb steering, and haphazard rear-axlelocation make you wish that Callaway engineers had focused alittle more of their expertise on handling gains. Despite wider wheels and tires, there was no measuredimprovement in stopping distance, but it's a sure bet that thismodified edition will stand up to repeated hard use withsignificantly less brake fade than you'd find in a stock ImpalaSS. As is the case with any aftermarket effort, there are a fewshortcomings to report. The super wide front tires need constanthelp from the driver to keep the car in one lane on the highway.When the back seat is occupied, the rear tires occasionally brushthe fenders over bumpy roads. Fortunately these are minorirritations that do little to diminish the day-in-day-out drivingenjoyment that's baked into this overachiever. The fact that Callaway's modifications cost more than thecore car means there won't be a long line of customers beggingfor GM's assembly plant to work overtime cranking out Impalas forSupernatural conversion. Nevertheless, as a demonstration of whatcan be done with conscientious re-engineering, the CallawaySupernatural SS is a shining example of the classic all-Americanmuscle machine. RELATED ARTICLE: TECH DATA Callaway SuperNatural Impala SS GENERAL/POWERTRAIN Body style 4-door, 5-passenger Vehicle configuration Frontengine, rear drive Airbag Driver Engine configuration V-8, OHV, 2valves/cylinder Engine displacement, ci/cc 383/6271 Horsepower, hp @ rpm, SAE net 404 @ 5750 Torque lb-ft @ rpm, SAE net 412 @ 4500 Transmission 4-speedautomatic Axle ratio 3.23:1 DIMENSIONS Wheelbase, in./mm 115.9/2944 Length, in./mm 214.1/5438 Basecurb weight, lb 4160 Weight distribution, f/r, % 55/45 Fuelcapacity, gal. 23.0 Fuel economy, EPA city/hwy., mpg 16/24 CHASSIS Suspension, f/r Control arms, coil springs/live axle, coil springs Steering Recirculating ball, power assistBrakes, f/r Vented discs/vented discs, ABS Wheels, f/r17x9.5/17x11.0, Forged Line forged aluminum Tires, f/r BF Goodrich Comp T/AZR, 275/40ZR17/315/35ZR17 PERFORMANCE Acceleration, 0-60, sec 5.9 Quarter mile, sec/mph 14.0/100.3Braking, 60-0, ft 115 Slalom, 600-ft, mph 63.6 PRICE Base price $ 24,405 Callaway modifications $ 25,345 Price astested $ 49,750

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