[Sailfish]

D111,
I have the same engine/carb setup as you (342 Roush/770 Holley) and experienced the same condition you described. I tried many different fixes to the carb, and managed to find a combination that eliminated the worst of it. However, the condition still remained. I contacted Holley and they ultimately replaced the carb at no charge. Holley was decent enough to indicate they had a batch of carbs that experienced the problem. Anyway, after receiving the new carb I bolted it on and the condition was resolved. I would encourage you to contact Holley to see if your carb was one of the problem children.