Turning a base-model Corvette into a supercharged, big-block behemoth is a dream come true for Jay Adams, a 35-year-old contractor from Mobile, Alabama. We recently ran into the car at this year's YearOne Experience, where it was making its public debut.
"My passion for Corvettes started at an early age," Adams recalls. "When I was three years old, my dad purchased a '70 LT-1 convertible Corvette. From the very first time I saw the car, I was totally fascinated. I thought it was the baddest thing on wheels I had ever seen. I would sit for hours in the Corvette, pretending I was driving it, making engine sounds with my voice as I toyed with the gear shifter. From that moment on, I was a Corvette addict."
Adams passed his grade-school days poring over the latest issues of VETTE, reading about high-performance Corvettes. It was then that he learned about the legendary ZL1-the race-spec, aluminum-block 427 that found its way into two production Corvettes in 1969. "This combo, with a few mods, headers, and a good tune, was worth well over 500 hp and would propel a C3 shark into the 10s," Adams says. "I knew I had to go in this direction when it was time to build my very own Corvette."
In 1996, Adams began a five-year project to restore his dad's LT-1. With that job successfully completed, he decided he had developed the skills required to build his big-block dream car. Five more years passed before he began the project. "In 2006, my friend Don Brooks offered me a '72 Corvette coupe for a decent price, but it needed a full restoration," Adams says. "The car was trashed cosmetically. The T-tops leaked, and rain had filled the interior with water. The seat frames were rusted, and most of the interior was covered with mold and mildew. But the overall condition of the frame and body was very good; there was hardly any rust or corrosion on the chassis or the structural parts of the body. The engine was a non-original 350, [so] I immediately thought back to my dream of building a ZL1."
Realizing that he was on a tight time schedule to make it to the '08 YearOne event, Adams commenced the disassembly, spending three laborious weeks stripping and cleaning the Vette. Then, he removed the body from its chassis and delivered it to Willie Byrd of Mobile, Alabama, who sanded the shell laser-straight. Byrd then sprayed the car with PPG K 36 Prima Urethane Primer Surfacer, followed by PPG Deltron (DBC) 2000 Silver Poly Basecoat and PPG DPU 2021 Concept 2021 Clear.
Meanwhile, Adams went to work on the Vette's new powerplant, starting with a GM Performance Parts ZL1 aluminum block (PN 1237085). Since Chevy's 427 and 454 engines share a bore size of 4.25 inches, he decided to up the ZL1's ante to 454 ci by outfitting it with a GMPP 4.00-inch forged crankshaft (PN 3963524), 6.135-inch Crower rods, and JE blower pistons. GM aluminum oval-port aluminum heads (PN 12363390) feature a 290cc runner volume, semi-open combustion chambers, heavy-duty pushrods, roller lifters, 2.25/1.88 valves, and high-performance valve springs. A Crane custom-grind cam orchestrates a fortissimo valvetrain symphony with 226/234-degrees duration, 0.587/0.610-inch lift, and a 112-degree lobe-separation angle. The melody is accented by Hedman Hedders and a 21/2-inch custom exhaust with 3-inch QTP cutouts. For reasons that will soon become clear, the compression ratio is a tame 8.5:1.
Instead of fiddling with carburetion, Adams installed a modern fuel-delivery system: a FAST XFI with an Accufab 4150 throttle body, Edelbrock fuel rails, Siemens 65-lb/hr injectors, an Aeromotive fuel-pressure regulator, and an Edelbrock Victor Jr. EFI intake manifold. Ignition, however, remains traditional: an MSD 6AL box and ACCEL dual-synch distributor routed with Packard 8mm wires to AC Delco R43XLS plugs.
The chassis and suspension were next. Adams painted the frame satin black and installed Shark Bite aluminum upper A-arms, QA1 adjustable coilovers, and a Vette Brakes and Products sway bar. The rear, meanwhile, was upgraded with a VBP modified transverse spring and Vansteel offset trailing arms.
Adams then mated the body back onto its frame and continued the drivetrain installation, bolting up a TCI torque converter with a 2,500-stall speed, a GM 4L80E computer-controlled trans, and a TCI stand-alone management system. A modified stock driveshaft connects the trans to a rebuilt GM Posi rearend with heavy-duty yokes and 3.55 gears. Braking power is dele-gated to factory discs with drilled and slotted 11.8-inch rotors, while 18-inch Boyd Coddington Junkyard Dog wheels wrapped in BFG KDW-2 rubber keep the Vette firmly planted at all four corners.
Adams' interior restoration includes factory thrones recovered with OE-style material, a stock steering wheel, and reproduction cut-pile carpet. Amenities include Auto Meter Phantom gauges, an Alpine head unit, Rockford Fosgate amps and subwoofer, and MB Quart speakers.
Comfort tweaks aside, the most noteworthy aspect of this ZL1 Vette's amazing story is its ProCharger F-1R blower. "I was confident the ZL1 could handle 600 hp on its own, but my goal was 800 hp," Adams says. "I wanted the ultimate shark that would perform in every area, have all the creature comforts of a modern car, run on pump gas, and still supersede the power output of the legendary ZL1. But, fitting the F-1R supercharger in the stock engine bay without cutting or modifying anything posed a few problems. I had to spend many weeks modifying the supercharger's hat, and fabricating brackets and piping.
"I also intended to run an intercooler, but the C3s are limited on space up front. As an alternative, I went with a Snow Boost Cooler methanol-injection unit to control detonation. It's computer-controlled, begins spray at 4 psi, and hits full output at 15 psi. I utilized the stock windshield-washer tank for this application."
Adams also modified a donor L88 hood by removing the airbox and molding an electric vent door into the underside of the cowl. It opens when the electric fans are activated and helps reduce engine heat. The hood-support rail was also reworked to allow clearance for the massive F-1R.
Finishing the car in time for this year's YearOne Experience proved to be even more of a challenge than Adams anticipated. "There were numerous fitment issues that came with the mods, so it wasn't just a matter of bolting stuff back together," he says. "I went into hibernation almost every weekend for several months to meet my deadline. I even had to take two weeks off from work right before the Experience to finish everything. I cranked the car for the first time Wednesday night before the event, and we left for the show the very next morning. All the hard work paid off, as I was able to take First Place, with many positive reviews."
His hard work completed, Adams has every reason to feel proud of what he believes is the only supercharged ZL1 Corvette in the world, a supercar that drew its inspiration from his very first time in his father's Vette. "I plan on using the car for shows, Corvette club functions, cruise-ins, and leisurely drives," Adams says. "I also plan on taking it to the track on occasion. It's my dream come true."