The edelbrock carbs have a lean off idle problem, i only recommend using a 650 or lower cfm edelbrock on any application because of this but:
the idle channel restriction (ICR) is too small for the idle system so the idle system runs out of fuel flow before you get into the main circuit. look in the carb owners manual and you can see where it is. we remove the brass restriction over the ICR and then enlarge the ICR a few thousands of a inch at a time to make the idle and off idle system more active. this workd very well on the 600 performer and 650 cfm thunder but on the 750 it only helps since the rest of the idle system passages are too small. these changes have been done to the 800 cfm edelbrocks but it is not enough to solve the problem (in my opinion)if you want to see pictures of this the july 2006 issue of Corvette Fever has a article called tuning to perfection with more detail in it.
you can see this lean at off idle condition with tools such as a wide band oxygen sensor based air/fuel meter or a 5 gas exhaust gas analyzer.
i hope this helps henry @ oles carb
1971 Dodge Charger Superbee 2011 Ram Sport 1500 Quad Cab Deep Water Blue Loaded Siberian Huskies
