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Discussion Starter #1
need help with correct idle speed and timing advance for 69 mach 1 351 W.
car has 4 speed with 4 bbl carburetor, no air, power steering or brakes. I was told
it has a motor sport cam # SM-6250-A 351
 

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Really hard to say as there are so many other "unknowns" about your engine.

I'd start with a base (initial) timing setting of 12*BTDC and increase it in 2* increments, while road testing, until a slight "ping" occurs, then back it off 2*.

As far as curb idle, with a manual transmission I'd probably shoot for 700 rpm.
 

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Discussion Starter #3
Thanks for that info. I tried all of that and i think the timing issues are OK now. I am beginning to think my idle issues is with the carburetor. can't get it to idle under 900 RPM.
I am using the original style autolite 4100 series maybe need to upgrade? i tried to adjust the mixer screw by turning them all the way in then out 1 1/2 turn but had to turn out 2 full
turns just to get to idle at 900 RPM.
 

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Check that your fast idle cam is not sticking and that your secondary idle stop is properly set. Also check for a vacuum leak at the base and for a stuck open PCV valve.
 

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Could be as simple as misadjusted throttle linkage too? With the blades hanging open just a tad it makes idle really hard to set. Try 'forcing' the blades more closed (gently) and see if it improves. Verify that the idle speed screw's not holding it open too, obviously.
 

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Discussion Starter #6
Thanks guys for all help. It was a carburetor issue. I used a loaner carburetor to swap out and took care of the problem. Now I have time to take a closer look at my carburetor to figure out the problem.
 
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