The Cobra is an awesome car. I worked for a guy in High School that owned a plethora of Cobras and Shelby Mustangs. I have driven 260, 289, 427 and 427SC Cobras. I have driven race prepared 427SC Cobras on the track. I KNOW what a Cobra is.
The bottom line is read into why Gurney developed the Daytona Coupe. The Cobra is aerodynamic nightmare. It was the best of the best in its day. It's day is past. If you put the safety equipment in it that is required by 2004 laws you would have to add probably 600 lbs to the car, killing your weight advantage. At the same time, if you get rid of that weight in a Z06, you would have a car capable of handing the Cobra its hat.
The Cobra body generates no aerodynamic downforce, which the Corvette does, giving high-speed cornering to the vette. The Corvette is slippery enough to reach speeds of over 200 mph on 600 hp, which will take the Cobra to about 170.
Sorry, but 40 year old technology just is not competitive, even Carroll will admit that. Otherwise, Cobra's would have won the GTS Class at LeMans sometime in recent history, which seems to have been won by... hmmmm Corvettes in 2002. When you compare apples to apples there is no contest.