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Holley Idle 2 schools of thought

699 Views 15 Replies 5 Participants Last post by  PRNDL
So which school of thought do you guys recommend as far as idle is concerned?

Secondaries closed with just a small 1/8 turn to prevent binding. Then set the idle via the primaries only?

or…

Secondaries adjusted to match the exact same level as the primaries. Then make idle adjustments by adjust both fronts and rears the exact same?

Both methods assume the primary transitiin

AED Holley 750 HOHP DP 4 corner idle. Came with 1/8 holes in primaries only. and PCV hooked up. One inch open spacer.

The engine is a freshly rebuilt 383 stroker. All machined, brand new stroker internals, 30 over, zero deck, 6 inch rod Skip White unit with 10cc dished pistons. AFR 195 heads, Performer RPM AIR GAP, dual plane, and Comp Cams XR282HR 230/[email protected] 110LSA CAM. HeadersBreak in has been completed.


I’m noticing that if I set my idle to 900 rpm via the first method, primary adjustment only, my rear idle mixture screws stop responding. I can screw them in all the way and no change.
When I set the idle via the second method, primary and secondary matching, to 900 rpm, the front mixture screws stop responding.

I’m thinking of lowering my idle to 800 rpm.

Any ideas?
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I always set them with around 60 percent idle rpm on the rear so the fronts are on the idle circuit a little longer at tip in. It works well and the preferred method of many custom carb builders.
 
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