Hi All,
As you all know, I recently replaced the stock intake on my 83 z-28 with a older Edelbrock SP2-2 Intake.Installed no problem.Okay, next step, I replaced my dist with a vacumn advance one,Third step, I have tried 2 different carbs(One is a Holly and the other a Edelbrock).No matter which one i try,I cant get my idle down.I have made sure I have no leaks,and made sure all vacumn ports are being used or capped off.On the edelbrock,I try to adjust the idle scews,and no change on idle.With the Holly,same thing.Am I missing something here?

Smoothjazz

 

Assuming you know the difference between the idle-speed screw and the idle-mixture screws, I'd say that you have to have a vacuum leak. You said you capped off all vacuum ports. Did that include the line to the brake booster?
Do you have a good matching gasket between your carb and the manifold?
If your manifold has an EGR provision, is that blocked off/sealed?

 

I have a good seal.Everything that is not being used is capped off.I am lost what else it could be.like i mentioned ,when i try to adjust the idle screw on the top right of the edelbrock carb,nothing changes at all. i figured it must be a vacumn leak.i cant find anything at all that would be causing my problem.

 

I agree, you've got a vacuum leak somewhere...the problem is finding it. Have you checked the vacuum advance can? Pull the hose off the carb, stick it in your mouth and suck, put your tongue over the end of the hose. If it won't hold, you've got your answer.