I did, we were all correct, I'm a big dummy!
Header gasket. The slightest, smallest, burn path thru a header gasket I've ever seen, in the most inaccessible place. Pointing straight down from the #3 cylinder, iirc. Left no exhaust mark, and couldn't see or feel it.
That hose trick saved my butt. I think it was one of those things I knew at some point but got pushed out of my brain as there wasn't enough storage space.