It still sounded like it was near the exhaust to me............for what its worth, the noise seemed to get louder near the rear of the engine bay when you had it closest to the exhaust. It is just a video and could have been the recording equipment. Do you have a way to get it up on jack stands or on a lift and listen for an exhaust leak from the underside of it? I really don't think it is anything with the lower half of your block from the info that I have been given on this particular thread.(although it is not impossible.)
