strange idle

here is a problem i have been working on for a long time now and still havent found what is wrong, my 340 idles pretty rough at 800rpm wish is not a strange thing because of the big rollercam but if i rev it up some to impress my neighbours or something like that when i let of the thotle it wont go down to that low idle again it levels at 1400rpm wish is way to high in my opinon, i have tried to turn it down by using the idlespeed adjustment down but that does not work if i shut the engine of and restart it will idle at the normal idle speed, this is not a big problem during normal driving since the whole drive train will pull the rpm down to that low idle when i stop at a traficlight but it is verry anoying, it also has a small problem with of idle hesitaion but that has is not a primary problem.
engine has a hooley strip dominator intake manifold and an edelbrock 800cfm thunder series avs carb (had the same problem with the holley 650 dublepumper that was ther earlier) it is equiped with an msd pro billet distributor and an MSD 6A ignition box engine has 11:1 compresion a big solid roller cam ported J heads and runs like hell its just this small problem!

thanks in advance!