[DanEC]

One suggestion I received was to get something to serve as a long wand (heavy piece stiff wire for example) tape a small tuft of tissue paper to the end of it. Then move it around each connection looking for exhaust leakage to move or flap the tissue paper. Sounds good - harder to do in real life as any contact of the wand to the body or engine component will set it to vibrating and with limited space in the engine compartnment that's a big limitation.

As a one in-a-million lessons learned - I had an exhaust leak and finally discovered that the last time I slipped my header on I left the lower bolts/washers in the head for the lower bolt slot in the flange to ride down on and hold the header pipe while I threaded in the top bolt. What I didn't catch was that on one cylinder, the flange slid in between the washer and the bolt head, trapping the washer against the head/gasket. Made for a rather persistant leak until I finally discovered it.