Holley Jetting question
Jetting alone will not fix the rich cruise situation.
You need to learn about the idle feed restrictors, Idle air bleeds, power valve channel restictors to get a handle on the cruise situation.
It's some boring reading, but, the innovative site has some good tuning suggestions/theory for holleys in their forums.
Chances are you need a much smaller IFR, bigger PVCR and other tweaks to get it to come around. The newer holley DP race series carbs are really bad for this issue.
Take some no-doze before reading this stuff... LOL
http://www.innovatemotorsports.com/forums/showthread.php?p=71662
http://www.innovatemotorsports.com/forums/showthread.php?t=3134&highlight=avenger+870
Same basic stuff you need to deal with and plenty of theory to put you to sleep.