The intake is an excellent one.
The distributors vacuum advance on a Edelbrock carb should connect to the left port as you look at it. Where is the distributor set at? (You did set the distributor up without the vacuum advance connected right?)
Regardless of how you jetted it or what springs you have in the carb, it has nothing to do with the idle speed. Even more so evident since it issue down once you pull the vacuum hose.
This leaves me to believe the springs in the distributor are very light and not stock.
