So I'm trying to find where the exhaust smell is leaking from between my header to cat... behind the motor inbetween the cat it sounds like an air compressor and I feel a little air coming from the back of the block. Does this residue help diagnose at all? lol. I need to do a new head gasket seal anyway... hoping it's just that. I don't see a crack at the cat.

There's a pre-cat up near the head, above the flex joint, and the cat at the bottom. A lot of times the welds at the pre-cat crack. There was a post in the last few weeks of one and how they had a local shop weld it.

That's where mine broke after a moron worked on the exhaust.

I guess the pre cat is actually below the flex joint. Here are a couple of pics from another post.

Ahhhhh.....
That could
be it. I have the Stratmosphere cat back system so I wasn't even thinking about after the flex section. I'll jack it up this weekend and scope it
out down there 😁✋🏻