As an active member of the Impala SS Club of America and owner of three B-bodies, it should come as no surprise that Chris Nickell chose a '95 Impala SS as the basis for a competitive bid in the NASA American Iron road racing series. This makes it no less bizarre, though, when Chris's Dark Green Grey Metallic Impy sedan passes much smaller and lighter Mustangs and F-bodies on the tight confines of a road course. The 38-year-old Illinois native first hatched the scheme at the 2003 ISSCA Nationals, after hauling his '96 Impy drag race/show car around the Hallet Motor Racing Circuit in Tulsa, Oklahoma. Since then, his '95 DGGM race car has been devoted to providing hope to B-body enthusiasts everywhere.
Since its purchase in 2004, it's been a long, hard road to get the 167,000-mile retired police cruiser into racing shape. After quite a bit of elbow grease, Chris managed to scrape off all the northern Illinois rust, and coat the frame and underside of the body with POR-15, before sandwiching Energy Suspension poly bushings between the body and frame. His cousin Paul Mason also helped with a little more bodywork, and with painting the Impy Dark Green Grey Metallic. The stock steel hood was traded for a Glasstek fiberglass pin-on hood, as the first of many steps taken to lighten up the broad-shouldered beast, while an aluminum wing increases downforce to keep the behemoth from busting loose at high speeds. The interior was completely gutted, and taken to Cowdry Fabrication for a six-point NASA-spec rollcage with NASCAR doorbars. An aluminum sheetmetal dash was also fabricated to house a host of Auto Meter gauges and a Longacre push-button start. A Rebco quick release steering wheel, Kirkey racing seat, G-Force six-point harness, fire extinguisher, RJS window net, Percy's Speedglass windshield, and Lexan windows complete the race car transformation.
For weight distribution, the PCM, fuse block, and battery were all moved to the cabin. In addition, Chris moved the motor mounts back as far as possible, since the firewall can't be modified (per AI rules), and a 383-cube LT1 built by Mullins Race Engines now sits 1.5 inches further back in the B-body's front end. Equipped with JE flat-top pistons, Eagle H-beam forged rods, and an Eagle forged 3.750-inch stroke crank, the 12.0:1 compression Gen II can reliably spin to high rpm with a COMP Cams High Energy Cam. A Melling high-volume oil pump, Moroso Oil Accumulator, and Canton Road Race oil pan help keep the Clevite bearings and Total Seal rings happy, and an AFCO aluminum stock car radiator was necessary to dissipate the brutal heat produced by a day of hotlaps. Though it ultimately boosted Chris into the American Iron Extreme class for exceeding the 9:1 power-to-weight ratio, a 232/246 duration, .555/.576-inch lift hydraulic roller, and Air Flow Research 195cc LT4 heads were the chosen power producers. The CNC-ported aluminum castings came complete with 2.02 intake and 1.60 exhaust valves (as well as 1.53-inch valvesprings), so all it took was mild porting by Lloyd Elliot to free up power under the curve before bolting them up to the stroked LT1, inserting Manley hardened pushrods, and affixing COMP Cams Pro Magnum 1.6 ratio steel rockers. The stock intake manifold was ported to match the heads and a Holley 52mm throttle body, and was assembled with SVO 30-pound injectors fed by a Walbro 255-lph fuel pump. A PCMforLess tune and mostly stock ignition keep the LT1 amicable, and with the help of Jet Hot-coated Flowtech 1 5/8x3-inch long-tube headers (originally made for a Second Gen Camaro), and Dr. Gas 3-inch X-pipe and Boom Tubes, the powertrain was ready for action.
Heading into the turns, Chris feels confident in Wilwood SL-6 six-piston front and four-piston rear binders. Wilwood Polymatrix pads, along with the 13x1.375-inch front and 13x1.125-inch vented rotors, resist brake fade. The substantial braking system easily clears the lightweight Forgeline RS 17x9.5-inch racing wheels, which adorn spec 275/40R17 Toyo RA1 rubber. The rear is fortified with a fresh Motive 3.42 ring-and-pinion, Moser billet pinion yoke, DTS differential cover, and Torsen T2R limited slip differential, while still rocking the stock axles. Additionally, the 8.5-inch 10-bolt is connected to a Tremec TKO 600 five-speed trans, with a road-racing gear set via a 3-inch chrome-moly driveshaft from Keisler Engineering. Retrofitting the manual trans only required poking a hole for the Hurst shifter to protrude into the cockpit and fabricating a crossmember, as well as acquiring a clutch pedal from The Horsepower Factory and a steel bellhousing from McLeod. The New Age Motion high-torque clutch and pressure plate, lightweight GM flywheel and hydraulic throw-out bearing are used to engage the 383.
Even with all the modifications made to lighten the Impy, the long-wheelbase sedan still tipped the scales at 3,460 pounds, which meant that it would take serious suspension tuning for Chris to keep up with his lighter competitors. The first step was dialing-in the alignment and steering. Given the limited amount of front-end and steering components for B-bodies, Chris fabricated several pieces to be shared with other enthusiasts via his company Rustic Racing. A power steering cooler and aluminum reservoir keep the fluid in check during road course and autocross flogging, while tubular DOM upper and lower control arms make way for solid nylon and steel bushings, Moog K727 lower ball joints, spindles, G+ Suspension spindle spacers, and Bilstein shocks. Rustic Racing 850-pound linear race springs and a 1.25-inch sway bar firm up the front end to work in concert with a looser rear end (to control oversteer), and the stock rear sway bar was deemed sufficient for optimal handling while using adjustable Rustic upper and lower control arms, relocation brackets, and a coilover kit. Chris has created a completely tunable rear suspension with the ability to center the wheel in the wheelwell (a common problem on B-bodies) and the adjustments to the pinion angle, thanks to the spherical-rod-ended control arms, as well as the adjustable ride height and preload with Rustic 175-pound springs and Bilstein shocks.
Through fine-tuning his entire combination (including his driving), Chris has managed impressive showings at a number of NASA, SCCA, and ISSCA events, helping to spread the word on the B-body's awesome potential, given the right setup. Even if the current class rules keep the Impy off the podium, the unconventional GM-stamped challenger certainly gives pride to the spirit of the rear-wheel drive, American muscle racing series.