[Brad]

Originally Posted by cell

very interesting grunty -- as a matter of fact that is exactly how it is failing, and my carb (a single bbl rochester) is permanently jetted too rich (apparently torque was more important than fuel economy back in the day).
I never would have considered that a rich mixture could have been the culprit. Thanks for the suggestion.

, interesting. I never would have guessed. Anyway, I've had some problems in the past with that and always thought it was a leak in that area and that the tailpipe wasn't aligned properly with the exhaust manifold along with being too rigidly held in place.