Camaro SS and Corvette ZR1 On Road Course
 

Either there is no sound in the Camaro part at the beginning or that car has wwwaaaayyyy too much muffler on it.

Its raw video, so the mic only picked up whatever noise it could. Its unedited and there was no mic on board the car to pick up the true sound.
There were video of the V6 and V8 Camaro running around with the 15 Deciples driving them, both exhausts could be heard very clearly.

I think someone already posted this, I posted a DL link in the thread.