Before heading out, the two main questions on my mind were: How would the stock Grand Sport suspension and brakes handle the significant increase in horsepower? And second, how would the automatic transmission perform in concert with the supercharged engine? I was fairly confident that the Grand Sport underpinnings were up to the challenge; after all, they are nearly identical to those found on the 505-horsepower Z06. As for the transmission, I had my doubts. I’ve driven other supercharged C6 automatics, including a Callaway C16, in which the gearbox and the engine seemed to speak different languages. Admittedly, these cars featured early examples of Chevrolet’s paddle-shift transmission that were slow to heed commands.
It took me only a few corners to discover that Chevy’s automatic and Callaway’s SC606 package make a fine pairing. Left to its own devices, the transmission performed well, holding gears long enough to enjoy the full breadth of the supercharged engine’s powerband. However, I wished the transmission would downshift more aggressively in full automatic mode. For this reason, I much preferred using the paddles on track. My pushes and pulls were met with rapid up- and downshifts.
The red Grand Sport felt no less rapid than the silver one I had been chauffeured around in. This is one fast Corvette: It simply inhaled the track’s short straights, careening into triple-digit speeds with almost frightening urgency. Thankfully, traction was not a problem, allowing me to get hard on the throttle even out of the slow corners. The SC606 engine doesn’t have as much high-rpm pull as an LS9—Callaway’s SC652 package, with its electronic fuel-pump controller, apparently has more top-end power—but that hardly constitutes as a demerit.
When it came time to scrub off speed, the Grand Sport’s Z06-spec brakes were up to the task, providing rapid retardation and solid pedal feel. The pedal remained firm throughout my time on the track, but I wouldn’t want to subject the brakes to repeated hot laps, especially with the standard brake pads.
As for the suspension, I’m pleased to report that it performed admirably. Sure, the car exhibited a bit more lean in the corners than the coil-over-equipped Grand Sport, but the handling balance remained pleasingly neutral. The additional weight of the supercharger and its related hardware doesn’t cause understeer to rear its ugly head; the car still turns in with satisfying immediacy.
The stock Goodyear F1 Supercar tires are probably the car’s weakest link. Though they still allow for extremely high roadholding limits, stickier rubber would definitely be welcome on track. Automatic-equipped Grand Sports can’t be ordered from Chevrolet with the much better-performing second-generation (G:2) version of the tire, which is a bummer. Prospective customers who plan on taking part in more than the occasional track-day event would be advised to purchase upgraded rolling stock.
Knowing that Harchelroad Motors was still looking for a buyer of this untitled Grand Sport—its Harchelroad-applied white stripe atop the optional Callaway C16 hood should appeal to Nebraska Cornhusker fans—I headed into the pits. Right on my tail was a white Grand Sport convertible. The car had loomed increasingly large in my rearview mirror during my last lap; its driver obviously knew his way around the circuit and wasn’t afraid to hammer his Callaway.
That driver was Scott Bartels, who had driven out from Lincoln, Nebraska for the day. Bartels is a longtime Corvette enthusiast, and a serious C4 afficionado. To finance the purchase of his new Grand Sport, he sold off four of his C4s. The one he kept was an ’87 Callaway twin turbo, the second B2K-optioned car ever made. The idea of owning the original Callaway Corvette offering and the latest appealed to Bartels. “I wanted to own the alpha and the omega,” he said.
Bartels purchased his automatic-equipped ’10 Grand Sport convertible off the Harchelroad Motors lot in June 2010. The car was then shipped to Callaway in Old Lyme, Connecticut to have the SC606 package installed. Bartels took delivery of the completed machine two months later. “I’ve been ecstatic with it,” said the proud owner.
Part of a Callaway Corvette’s appeal for Bartels is the fact that “it’s not mainstream.” He said that most people aren’t familiar with the brand. Another factor influencing his purchase was the fact that he could get a high-horsepower Corvette convertible with an automatic transmission—a combination that Chevrolet doesn’t offer—while still having a warranty. Of course, the Callaway’s performance was a big factor, too. “You’ll run out of guts before you run out of car,” he enthused.
Over the course of his first nine months of trouble-free ownership, Bartels says that the Callaway Grand Sport has renewed his enthusiasm for the Corvette hobby. “I had stepped back, big time,” said the formerly active club member. Since purchasing the car, he’s completed a driving school at MPH and returned to the track on a monthly basis. “I get treated like family out here,” said Bartels.
As it turned out, the timing of my visit to Hastings, Nebraska couldn’t have been better. A good number of the Corvette owners on hand were farmers, and they informed me that they had just managed to plant their soybeans a few days prior, allowing them the opportunity to take some time off and enjoy their cars. It was a pleasure to join them in this pursuit, especially with a Callaway Grand Sport SC606 at my disposal.