How to tell if a converter is bad or plugging up?

[acoen]

My 86' GN with 62k miles passed smog here in CA, with no huge problem. My question is how would you tell if a converter is going bad? The car runs fine, but it doesn't pull as hard as my 87 WE4 did with similar mileage and is much more quiet out of the exhaust than my 87 was. It almost acts as if the converter is starting to plug up. I have smog results or VIN if needed. It has factory exhaust from the headers to the exhaust tips. I know it's a silly question, but the quiet exhaust and mediocre performance is puzzling. If it is failing where would I go to get a new factory replacement converter. I prefer to keep my GN factory original. Thanks in advance for the help.

Aaron

 

[gofstbuick]

There is a backpressure test for a plugged catalytic converter. The factory converter is quite restrictive and changing to a high flow cat will unclog the exhaust system without any noticible changes. Jst make sure the muffler shop retains your factory cat hanger.