Well good luck on that,because thats going to be one hard task to overcome.
Let see top three time their are:
1.VIPER ACR 7.22.02
2.ZR1 7.26.02
3.Nissan GTR 7.26.07
Don't forget nissan gtr v-spec in japan has out ran the viper acr but still waiting for the result at Nurburgr.They claim that it will run 7.00 and some change