I think the GT will still have an edge on the Z06 - I think the FI 5.4 is still making more than 550 hp and it will still have a wider powerband than that NA 7.0 - not a lot, but some. It's making so much torque at such low RPM that there is no 1-2 shift before 60 mph, and that's part ofe1 the reason it will still own the Z06 by .5 second there.
I looked up some testing numbers of the GT and despite what the specs here and weight might hint at, the GT pulls superior numbers to these posted. So it'll be close.
One thing to take into account is that while the Z06 has a great weight balance by moving the driver and the transmission and tank as far backwards as possible to counter the engine up front, this still leaves lots of weight at the corners of the car (bad). The Ford GT has the driver and the engine and transmission all in the center of the car which should make it more flickable. Nevertheless, they are both beasts!
But regarding torque, we are talking about a 7.0 liter OHV monster here. Even with a regular Vette the CAGS have you shift from 1st to 4th gear for regular cruising unless you give it lots of gas or break a certain RPM (had this eliminated on mine). Torque issues aint gunna be no thang. And a supercharger does increase the effective displacement, but its a smaller displacement to start with. Either way, both are going to be shredding their tires to bits in lower gears w/o traction control on if the driver floors it quickly (even the 345mm tires on the back of the Z06), so thats kindof a moot point.
You know, Ford is really sandbagging on the output of the GT - I was just at the Popular Mechanics site (really do some serious testing there, as they always have), and the only car they could get for the comparison test that could beat the GT in the quarter was a Saleen S7. Now, this is a good comparison, because it's got a NA 7.0 liter engine (although PM mistakenly says it's supercharged in the spec box), like the Z06 does. It's making 550 hp and 560 tq., compared to 550 and 500 for the GT, and 500/500 for the Z06.
The Saleen ran 3.73 0-60 and 11.51 in the quarter. The GT ran 3.43 0-60 (no 1-2 shift!) and 11.69 in the quarter. Now the kicker - the S7 weighs 600 lbs. less (2750 vs. 3350) - it's all carbon fiber. More food for thought - the GT was tested at another strip from the rest of the cars - with higher elevation, hotter temps and worse traction.
Yeah, right - the Ford's making only 500 lb/ft - at the wheels, maybe!
I would say that unless Chevy's sandbagging too, the Z06 will do 3.8/11.9.