Today will talk a bit about the "Idle-Eze Idle Air Control parts. Idle Air By-pass was used for years and years on the Carter AFB Pontiac carbs so Barry Grant did not invent that capability. Other people, like myself, made our own "Air By-pass" systems, (Tri-Power is extremely easy as you can add extra idle air with the end carb throttle blades). But we are talking about the Idle-Eze system that Holley now uses because they own Barry Grant's old Demon company.
This article by Maxchevy.com has great pictures so I will use it for explanation purposes.
http://www.maxchevy.com/printable.ht...20Rough%20Idle
The last paragraph in the article: 'On racing engines, the Race Demon carburetor introduces air at idle via a jet instead of the Idle-Eze.
The jet is supplied either in an un-drilled form or pre-drilled." I have been making 'jets' that fit the center area of Holley Base Plates for years.
You drill thru the air cleaner stud hole down to the cavity inside the main body and now extra air will be on one side of the "control jet" that is installed in the Holley Base Plate. If you do a Blow-thru Carb air cleaner stud mod (hollow stud) then the air comes from that location.
Or you can drill holes in the main body casting and use a solid stud to hold the air cleaner on. This is what Holley does today.
Read the article and it can give you lots of ideas.
Tom V.