Have you tried leaning out the mixture at all? I am not sure where the edelbrock air bleeds are, but why not try taking them back a notch, about 1/4 turn at a time on both sides, and see if that fixes the problem. Lean the mixture out a bit, then drive the car for a few days or a few cruises and check the plugs. If they are still black, then turn the mixture screws back another 1/4 of a turn and try again. Just make sure you keep all of the screws turned out the same amount.

Just a side note: I have had some highly recommended tuners mess up pretty bad. Everybody makes mistakes.