While hot rodding's historical imperative has always been to make as much power as possible, the reality is that the less mass there is to carry, the less power it will require to move it admirably. Tyler Powell's Grand Sport Corvette is a prime example of this physics lesson. It's a simple matter of economics. At a mere 2,590 pounds, it performs just as well or better with 370 wheel horsepower as much heavier cars with more than twice the grunt. The sidebar to this is that the lighter vehicle is likely to spend more time on the track and less time fixing the parts that the weight helped to compromise.
Tyler began his history with a relatively heavy car, of course. When he was in high school, his dad bought his mom a 1976 Corvette. By degrees, Tyler confiscated it, pumping his summer money into it year after year. When he graduated college and worked a real job, he did a body-off resto that included an LS engine and a T-56 transmission and he underwrote them with muscular suspension and gritty braking programs.
He liked the results he realized with the 1976 but hankered for a clean palette, a platform that could be customized along the way. He sold the Corvette and seriously considered a Factory Five Daytona Coupe or Cobra. The Chevrolet equivalent, however, was being celebrated at Mongoose Motorsports in Ravenna, Ohio. Among other pertinent bloodlines, Mongoose produces replicas (in various states of completion) of the Grand Sport Corvette, which seemed just the ticket for Tyler. He rang up Gary Krause and ordered a deluxe package, a roller that included the gel-coat fiberglass body, a round tube frame, and a box full of optional parts. By July 2010, all the stuff was sitting in friend and co-worker Justin's big-floor garage.
Tyler drew confidence from this experience. He learned how to prep and sand the fiberglass. He learned how to sew. He learned how to build from scratch. Two months in, he took the Grand Sport for its first test drive, completely bare save for body, frame, and a stock LS2 engine. He was impressed with the raw product. It was a poignant moment, and one punctuated by large quantities of energy drinks. For the following seven months, he thrashed on the body, paint, and interior, all the while driving the Mongoose to work every day.
He wanted his race car to be street-friendly, too, replete with audio as well as frigid air. He envisioned a one-off interior treatment, but the nearest such Mecca was Mobile, Alabama, about 60 miles from his home. The inquiries he made about upholstery jail were so off-putting (1-2 years!) he decided he'd learn to operate a sewing machine. Everything was a custom deal; there were no off-the-shelf parts. And since the interior was such an open proposition, he could customize at will.
Then he went a little crazy, maybe from all those Rock Star cocktails. In early 2012, he decided to sell the work, "mostly because I wanted to build another. Luckily, right before I was to set up the transaction for the sale, I snapped out it. I decided to build upon what I'd already created."
And what he'd created has produced pleasing results so far. He's run a best of 11.6 at 123 mph at the dragstrip, and in the Grand Sport's first official outing at the 2013 Holley LS Fest, he placed 14th out of 93 entries in the autocross, slicing and dicing the course in 37.620 seconds. From strap-operated side windows and faux snakeskin vinyl to the big ol' hairy side pipes shooting flames, Tyler Powell is looking for the next big thing.
A mildly hopped 6.0L LS2 out of a 2006 GTO provides more than enough moxie for this lightweight ripper. Employing low mass amounts to big savings on the engine build. No need for a raft of aftermarket goods, extended testing or a zillion horsepower, so modifications to Tyler's engine are mild and rudimentary. The engine is basically stock and has no changes to its bottom end (save for a Melling oil pump). Tyler swapped in a custom-grind camshaft (0.602/0.614-inch lift, 234/238 degrees duration at 0.050) specified by Patrick G. on ls1tech.com, built by Engine Power Systems in Baton Rouge, Louisiana, and installed it with a Katech C5-R timing chain. To make the most of the livelier events, the stock cylinder heads were outfitted with dual valve springs from Total Engine Airflow in Tallmadge, Ohio, and secured with titanium retainers. Chromemoly pushrods complete the scenario. The intake tract was upgraded with a FAST LSXR manifold furbished with a 102mm throttle body and a custom ram air chamber/box with an Airaid filtration system. Fuel is drawn from a modified Mongoose aluminum cell. MSD primary ignition wires compliment the remote (stock) coil packs. Those raucous but mandatory side pipes were custom-built by Stainless Works and maintain 1 7/8-inch primaries that merge with 3-inch collectors. On the dynamometer, the 364ci engine pulsed 409 lb-ft of torque at 4,350 rpm and 440 hp at 6,350 rpm. When Tyler got the GTO engine it had a 6-speed hanging off the back. He replaced the clutch assembly with one from an LS7 Corvette and serviced the gearbox with a rear-mounted oil cooler. The Precision Shaft Technologies driveshaft enables the 1996 Corvette Dana 44 axle assembly holding Posi-traction and a 3.45:1 gearset.
Essentially a kit car, the Mongoose uses a fiberglass shell affixed to a 4x0.120-inch round tubing space frame that accepts the LS engine, 6-speed transmission, custom coilovers and stock C4 suspension bushed with urethane. The dampers are Bilstein C4 ZR1 augmented by QA1 coils that offer a wide range of adjustability and work with Vette Brakes 1.0-inch and 5/8-inch diameter anti-sway bars and adjustable end links. Tyler aims his feathery dart with a C4 rack steering system. Simple as that.
The 1996 C4 spindles accommodate Kore3 13.4-inch rotors and Kore3 pads. The back brakes are C4 with Hawk pads. The bantam weight coupe sports some hairy rollers and ultimately recalls the proverbial roller skate. Tyler moves with forged, three-piece CCW Classic rims all around, 18x10 and 18x12, paired with fat boy 275/35 and 335/30 BFG g-Force Rival sneakers.
Wheelhouse flares, that high-zoot hood, the fender-mounted rear brake air ducts and clear-sealed headlamps are Mongoose mainstays but the Vengeance air dam beneath them is not. After a botched first-run on the paint, Tyler found Donny Moore at Don's Body Shop in Jackson, Alabama. Donny taught Tyler the proper prepping and sanding process … and then deemed it acceptable for paint. Ol' Donny laid down a perfect layer of Sherwin-Williams Carbon Flash Metallic base coat followed by CC930 clear. He finished the picture with Satin Silver Grand Sport fender stripes and hash marks.
Tyler did the interior, and he didn't have to go to Home Economics class to find out how, either. He looked at what he had, at what had to be done and he got self-taught. He began with the Painless wiring and made preparations for the audio system that includes KHE-300 head unit (w/iPod port), Rockford Fosgate P2D28 8-inch dual 2-ohm component sub-woofer in a custom 'glass enclosure (rear), Rockford Fosgate Prime R1653 6¾-inch 3-way speakers (in doors) and a Sound Ordinance M4050 amplifier. The leather-swathed seats are straight out of C6. The gauges are Auto Meter Ultra-Lites set in a no-frills panel. Tyler works the Grant Classic Corvette steering wheel with one hand and bang-shifts the Pro 5.0 shifter with the other. Since so uth Alabama really cooks in summer, he could not deny Vintage Air HVAC driven by a Sanden compressor (held with brackets from Kwik Performance, Inc.) Tyler went to work with his custom thread work and panel fabbing. He recreated the strap-operated side glass. Since the original Grand Sports were built to beat the Cobras, he was obliged to cover the center of the dash module and the shifter boot in faux snakeskin. He hand-formed the aluminum interior accents, sewed the carpeting and all the trim, headliner and the door panels as well. He hung the 5-point G-Force harnesses. He had the underbody sprayed with Lizard Skin sound control medium and insulated the cockpit with Second Skin Audio Damplifier Pro and Luxury Liner Pro for noise reduction and heat control.