He had me listen to the Fuel Damper which sits in the back near the firewall. Clank, clank, clank I heard very loudly.
I said Bingo!
Thanks bob1 for the info. I have noticed my MO sounds like what I describe as "like a dump truck" in the cabin. I have asked several people riding with me if it sounds loud to them but was always told no. It always sounded like loud exhaust to me. Not like an exhaust manifold leak which would sound more "tick, tickey" but more like a old street stock bomber running in the crash 'em up derby on Saturday night at the fair grounds. I will have a listen to my Fuel Damper and hopefully get mine sounding good again too.