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Old 06-25-2009, 02:31 PM
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Originally Posted by PatM
Cobalt327 -- I agree that the Vacuum Advance (14*) might be a bit much, but it is adjustable. I cannot recall it's initial and Full retard vacuum points (in hg). I expect this engine to idle with about 15 in hg. Do you have a recommendation for intial full retard vacuum levels?
I really can't hazard a guess as to the exact points, there's just no way to estimate it w/all the different variables (gasoline quality, jetting/carb tune, vehicle weight, rear gear ratio/tranny splits and if OD, cam timing, DCR, etc.), and even w/all that info, you'd be surprised at how differently one engine can behave from the next- even w/very similar set-ups.

I suggest that you start w/the vacuum advance can where it's at (obviously ) and slowly bring it in sooner and drop off later until it's maxed out, then regress back to a safe/sane point where you have no ping.

You can dial both the vacuum advance and initial/mechanical curve in after you've broken the engine in and are ready to hit the road w/it, but the set-up you've outlined in your first post is just fine for that purpose.
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