[Derding]

I have a 68 Firebird with a 300hp mild 400. On deceleration after a hard acceleration it pops like a popcorn popper. It has stock log type manifolds, and a 2 inch dual exhaust into one single muffler, and 2 tailpipes out of the muffler. Is this because there is too much back pressure? Or is it simply the muffler?

[Derding]

I have a 68 Firebird with a 300hp mild 400. On deceleration after a hard acceleration it pops like a popcorn popper. It has stock log type manifolds, and a 2 inch dual exhaust into one single muffler, and 2 tailpipes out of the muffler. Is this because there is too much back pressure? Or is it simply the muffler?

[firechicken]

Popping sound is usually a leak in the exhaust system somewhere. With the car jacked up and engine running, plug the tail pipe with a rag and trace the exhaust system listening for a hissing sound that would indicate a leak. Works every time.

[bonneville Joe]

Poping sound? I thought that guy was so old he couldn't even talk anymore. I guess that's better than a pooping sound though....

Give me a thumbs up, tell me "Nice Car!", but for god's sake, don't call it an Impala.