[JUSTINH]

I have dual exhaust flowmaster. One side is 10 years old and the other is 2 years old. Buick 401 , 65 Riviera. No heat riser flap.

What are the symptoms of a clogged side? I have exhaust coming out of both sides and it difficult to tell if its even.

[troy-curt]

About the only way the exhaust system con get plugged up, is part of the muffler come lose and get lodged someplace. Or if you have a double thickness exhaust pipe, the inner layer can collapse, I`ve seen this happen numerous times on original equipment exhaust systems.

you should hear a air rushing sound or a whistling sound,and a noticeable loss of power. If you suspect an obstruction, take one side at a time loose, and see if it runs any better. HTH

Good Luck
Troy

[jimfulco]

Get someone to operate the gas pedal while you hold your hand behind the exhaust outlet. Be careful, it's hot, & gonna get hotter. Tell them to gun the engine (in neutral of course) & if it blows real hard on your hand, it's probably not clogged. Compare the blow to a known good system if necessary.