Though initially influenced by the roar of a big-block, lots of things have changed since the ’60s. Now, the astute seem to gravitate toward the LS engine and its myriad configurations. They are appreciated for their six-bolt main bearing caps, the tenacity of the factory bottom end (except for two instances, they are nodular or hypereutectic not forged), and for their uncanny response to even the slightest modification. Brad got on the horn to Southern Performance Systems in Norcross, Georgia, prolific purveyors of OE LS crate and modified crate engines. One of their favorite configurations is a supercharged version, in this case an LS3 anointed by a Magnuson MP 122 blower restricted to 6 psi of positive manifold pressure. Southern fixed it with a blower grind COMP cam/hardware and set the compression ratio at a nominal 8.9:1. Patriot cylinder heads, built specifically for this mission, complete the long-block. They buttoned up the bottom end with a Corvette oil sump, presumably for the added ground clearance it affords. Burned stuff pulses through Sanderson 13/4 3-inch aluminized ceramic-coated headers. Output from the 376ci engine is 546 lb-ft of torque and 500 hp. Cooling isn’t limited to the engine’s AutoRad engine support or the aluminum core within. As a fact of life in the autocross world, power steering requires a dedicated cooler, which has been mounted on the passenger-side framerail. Torque is transferred by an LS7 clutch assembly to the Tremec T56, then to a Mark Williams driveshaft. Terminus is a narrowed (2 inches) Chassisworks Fab9 axle chocked with Strange Engineering 31-spline axles, differential, and a 4.10:1 ring-and-pinion.
Scrubbing energy is a constant in the autocross course, so the Atomic Beast is outfitted for consistency as well as bite-down power. The program includes conservatively sized Wilwood discs front and rear. Friction comes from the unusual tire and rim combinations: Boze Mesh 17x8 and 18x11 rims wrapped with 255/40 and 335/30 BFGoodrich g-Force KDW 2 tires.
The goal was to replicate the original interior, but conform it with unobtrusive upgrades and tweaks. Ken Ferguson at Kenco Upholstery in Cleveland, Georgia, built bucket seats reminiscent of the originals. Rusty Grindle replaced the dried, crusty spaghetti of old with an American Autowire harness and filled those main clusters in front of the driver with a custom Classic Instruments tachometer and speedometer. The three-pack ancillary under the stereo holds Classic Instruments as well. Since the Atomic Beast is a hands-down driver, HVAC was mandatory and Vintage Air came to the rescue. Other items of note include the ubiquitous Hurst shifter and Budnik crackling black GTO steering wheel stationed on a Flaming River tilt column. The safety restraints are Morris Classic Concept three-points. Since Brad would not do without melodies, American Radio in Cumming, Georgia, planted a Pioneer head unit, and ARC Audio 10-inch subwoofers and speakers. John March at American then finished off the trunk trim.
In front, Grindle began with a Chassisworks Ultimate Touring subframe that includes rack steering, tubular control arms, aluminum spindles, and billet VariShock coilovers. At the business end, an Alston g-Bar in conjunction with a triangulated four-link system and VariShock coilovers position the narrowed FAB9 housing. Hellwig antisway bars work at both ends of the vehicle.
Rusty had his way with the body big time, infusing lots of details that perfect the whole but aren’t readily apparent to most of us. You have to know your car and give close inspection to feel the changes. The Rod Shop’s Mark Wingo headed the strike force. The team fabricated a ’10 Camaro vent in the header panel, smoothed the cowl vent panel, and adapted C5 Corvette exterior mirrors. Then, they raised the cowl of the fiberglass SS hood a 1/2 inch, welded the front fender extensions as one piece, smoothed and tucked in the bumpers, and extended the lower fenders to match the rocker panels. In the engine compartment they wiped the firewall clean, located the engine coil packs under the cowl, put in the DSE mini-tubs, and smoothed the inner fender panels and matched them to the subframe. Very slick work indeed. CHP