The naturally aspirated LS7...
The naturally aspirated LS7 has been thoroughly freshened to produce 734 hp and 608 lb-ft torque.
The end result of his labors is a unique Z06 that is also a potent track car. As Birkness attests, "With the combination of downforce, power, brakes, etc., it is a very competent track car on the straights, braking, and in the turns." The car has been used at numerous HPDEs held at tracks such as VIR, Pocono, Beaver Run, Nelson Ledges, and Watkins Glen.
Birkness feels that his past racing experience gave him a good lead-up to the Z06, with motocross eliminating fear and karts teaching essential skills. He further attests that racing karts at 100 mph while one inch above the ground is a uniquely thrilling experience. "Things happen three times as fast on a shifter kart as in the Corvette; there is not time to think." However, he appreciates the more civilized nature of the Z06, as well as its ability to rapidly cover ground and push him back in the seat with spirited throttle application, even at high speeds. He also has adjusted from a racing mentality to one of pure enjoyment, stating that, "I just drive it as I'm comfortable that day, and my trophy is bringing the car home in one piece."
Fitment of the Phoenix Performance...
Fitment of the Phoenix Performance rollcage necessitated modification of the Z's door panels. Door speakers have been moved to custom cabinets in the hatch.
In spite of the car's track-oriented nature, it's still a capable street machine. The largest concern is some surging at lower speeds when driving in traffic. However, such an extreme setup demands a focused driver. As Birkness explains, "You have to be careful feeding the throttle, or it will snap sideways if there is any crown in the road." As would be expected, the primary issue is the Z06's attention-grabbing power. "Wherever I take it people want rides, but the problem is you can't show what the car can do on the street," he says.
With such an extensive array of modifications already accomplished, future plans for the Z06 are focused on tweaking the current package for optimal results. A cam with slightly less overlap is being installed, and the tune adjusted to reduce the low-speed surging. Ron Hutter is also working to strengthen the LS7's heads to handle higher spring pressures and rpm levels during extended track use. Birkness is also set on finding a way to replace the air conditioning, as the vented hood transmits heat from the engine compartment into the cabin.
The cockpit has undergone...
The cockpit has undergone extensive modification to ensure safety and performance at the track.
As with any such endeavor, Birkness has many people to thank for their help in the project. In particular he credits Kerry Hitt of ACP; Ron, Matt, and Trevor Hutter of Hutter Racing Engines; Kurt Omensetter of Phoenix Performance; Xtreme Auto Interiors; and Turner GMC/Buick. Above all others, Birkness is grateful to his wife for putting up with his hobby.
With a busy schedule as a partner in a large construction company and a standing gig as a bass guitar player in a few groups, Birkness does not get to use the Z06 as much as he would like to. But when he does, the car is both a stunning visual achievement and a celebration of the Corvette's racing lineage. As he sums it up, "It out-handles anything, other than the occasional non-streetable race car, and it hits 170 mph or more on some tracks. For a street car I drive to church, I think this is OK."