[mobius911]

Update- Installed the Dansk "stock" muffler over the weekend. Of course, the heat exchangers didn't line up, so I had to go through the whole loosening process. Took quite a bit of time but had no disaster with broken studs. In fact, everything came off ok once I had the right tools.

My original muffler is a Bischoff, and it has a 76 date stamp. Like John's, it's marked 3 years ahead of the car's vintage. Maybe it's like a freshness date? If so, mine lasted an extra 30 years...

Anyway, the car is running well and the I'm not experiencing any of the dreaded mid-range flat spots.

Thanks for everyone's input!