Marco,
You're pretty brave talking bad about FE's that way....
I don't think there are very many cobras out there with 500 RWHP. If you are going to put 500HP at the rear wheels you need a good bit over 600 at the crank. When you start pumping that much air, the sidepipes and mufflers tear you up.
There vast majority I'd say are in the 350 to 450 RWHP range. This would be between 425 to 550 crank HP. Besides, you could have 1000 RWHP in a cobra and struggle to get in the 10's without slicks and suspension mods.
Don't forget that your corvette has the motor and tranny sitting right on top of the rear tires (if it is new enough)..... a cobra has a little bit of aluminum or 'glass back there.