Quadrajet Problem Solving > Dialing in your rebuilt Quadrajet carburetor

idle issues

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wcumagic:
Cliff, it does have a vacuum of around 10 at idle. 

Ben Barnes (who did the heads) suggested the best timing should be around 36 degrees advanced with that cam.  I had backed it down a tad, maybe 34 ish and its happy. 

Cliff Ruggles:
36 degrees total timing is a "standard" answer for SBC engines.  It really depends on the final quench distance, combustion chamber efficiency, dynamic compression, octane rating(s), etc.

We shoot for about .035" quench distance with engines built here.  To date, with only one exception, all of them have wanted right at 30 degrees total timing for best power, and best ET/MPH at the track.

The one exception was a Pontiac 455 we built with 87cc Edelbrock aluminum heads.  They have "bathtub" chambers, and due to less efficiency that engine wanted right at 37 degrees total timing for best power numbers.

I like to see lower numbers, 28-32 degrees, as it's less negative work and frees up some power.  It also reduces octane requirments, and tendencies for detonation as well........Cliff

wcumagic:
I'll try your suggestion as soon as it gets above freezing around here, and post my results.  Thanks for your suggestions and help!

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