Backfire question 327

My 327 has been backfiring when I torque brake. Nothing real loud, just a pop, but it's getting annoying not being able to flesh out the problem.
The timing is fine and it runs like a champ. I even rolled the timing
back and forth a touch just to see if there was any affect, and there was none.
It doesn't do this any time except decelerating in gear. Any suggestions?
I know this has to be a simple fix, right?
-- lab~rat >:-) The less you care, the more it doesn't matter.
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Sounds like an exhaust lobe is wearing on the cam!
Common problem, sorry to say. But that's one ot the early signs.
Refinish King

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Do you have a Rochester quadra-Bog on it??? My buddy had the same problem. Think it was a bad plunger in the carb. In any case, check the carb. You have too much fuel going to the engine, for sure.

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On Tue, 9 Nov 2004 20:19:27 -0800, "James Alio"

Edelbrock. Same solution?

-- lab~rat >:-) The less you care, the more it doesn't matter.
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When the accelerator pump dries or shrinks:
It's usually the other way around. Too little or sporadic fuel spray on acceleration.
Refinish King

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On Wed, 10 Nov 2004 16:50:14 GMT, "Refinish_King1"

But I have NO symptom other than the pop. It idles smooth and accelerates like a charm. And it started over night.

-- lab~rat >:-) The less you care, the more it doesn't matter.
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Look for:
A loose exhaust rocker, an exhaust valve that doesn't open as much as the others. If you have points and condenser, look for a high dwell, simulating retarded timing. Maybe from not greasing the rubbing block on the points?
Refinish King

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On Thu, 11 Nov 2004 01:46:04 GMT, "Refinish King"

I'll look for an exhaust rocker, good point. I have a pointless setup now...
Thanks.
-- lab~rat >:-) The less you care, the more it doesn't matter.
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Do you have an exhaust leak either on the pipes or at the manifolds? On the over-run when you step off the loud pedal, unburnt fuel will ignite in the exhausts with air drawn in through any exhaust leaks and hence your pops.
I had it on my 400 Pontiac - I discovered I had poorly sealing / damaged gaskets at the centre exhaust joints on my headers. A set of good copper header gaskets solved the pops.
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My pleasure!
Refinish King
puked:

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