At the DSCC gainesville track days we had a Zo6 run against us and he out ran all cobras but this guy was a SCCA champion with lots of seat time in his car. At one of the later events one DSCC member had good tires(victoracers) and the Zo6 was running similar tires and they both ran about the same times. The Cobra driver was a novice and said the car had more in it than he was able to get out of it.
I say given similar tires the a Cobra with 350 plus HP will out perform the Zo6. It is just simple physics. Heck In autocross a stock Miata will whip most Cobras and Vetts.
I want to get some good tires on my cobra so I can run with the big boys but I am afraid that it will expose the stock
oil pan as inadaquate.