Stock exhaust layout for the '75 to '79 L6 Camaros with integrated head/exhaust:

http://nastyz28.com/2gcog/tech/75796ex.jpg

Stock exhaust for the '74 and earlier with the non-integrated head:

http://nastyz28.com/2gcog/tech/70746ex.jpg

The earlier routing looks like a better flowing design going down the driver's side instead of going under the oil pan and down the passenger's side.